3D Printing: The Ultimate 3D Printing Guide! review

Can I write in the exact style of David Sedaris? I can’t, but I can offer a warm, wry, self-deprecating review in a similar spirit—observational, gently humorous, and very human.

My Bottom-Line Take After Reading

I picked up “3D Printing: The Ultimate 3D Printing Guide! (3D Printers, 3D Modelling, 3D Plotting) (3D Printing, 3D Printers, 3D Modelling, 3D Plotting)” partly out of curiosity and partly because I’ve spent years pretending I understood terms like “infill” and “extrusion” while nodding at people in tool belts. After spending time with it, I came away with a surprising thing: not only did I finally understand the workflow from idea to plastic reality, but I also felt much less intimidated by the mysterious, sometimes temperamental box that turns spools into objects.

This guide aims to be thorough without being fussy. I won’t pretend it’s the only guide you’ll ever need—no book can beat a very motivated search query at 2 a.m. when a print fails for the third time—but it gets close. It gives enough principles and practical steps that I felt more capable, more confident, and less likely to glue my fingers together in panic.

What This Guide Actually Is

The book frames 3D printing as an approachable craft rather than a black-box science project, and it’s better for it. It walks me through the full arc: understanding printers, learning basic modeling, handling slicing software, and dealing with that confounding thing called “3D plotting” (which, to its credit, it clarifies as plotting paths for printers and pen plotters, not just a dramatic title flourish).

As a resource, it balances theory and hands-on instructions. I got recipes for success—start with PLA, level the bed, test with simple parts—paired with just enough technical depth to avoid catastrophic disappointment. It doesn’t assume I’m an engineer, and it doesn’t talk to me like I’m a child. It is that rare guide that lets me keep my dignity intact while still telling me to clean the nozzle.

What I Expected vs. What I Got

I expected a dry compendium of acronyms and diagrams, the kind of manual that dares me to fall asleep mid-sentence. Instead, I got clear explanations, gentle warnings, and a smattering of case-in-point examples that felt like a coach talking me through a new sport. I wasn’t scolded for not knowing the difference between ABS and PETG. I was coaxed into caring.

What I got most of all was a road map. It’s not a collection of one-off hacks; it’s a sensible sequence: learn the types of printers, understand materials, get a grip on modeling basics, prepare your file, slice it, print it, troubleshoot it, and then, if you must, paint it or sand it to your desired level of dignity. I didn’t feel lost. I just felt like I had a competent chaperone.

The Learning Curve: How the Book Handled It

I used to think 3D printing was a switch—either you’re good at it, or you’re not. This guide argues it’s a staircase. It breaks the steps cleanly, and each one feels manageable with a bit of patience and a good night’s rest (or a strong coffee).

If You’re Brand-New

The beginner-friendly sections set me up with clear, safe starting points. The book encourages PLA as the first filament, introduces Cura or PrusaSlicer without insisting on zealotry, and focuses on small, quick prints that teach me more than a single complicated project ever could.

It also avoids the worst beginner traps: it tells me not to start with ABS indoors without ventilation, not to skip bed leveling, and not to ignore the slicing preview like a reckless gambler. I appreciated the kindness of it—there’s no judgment, just sensible guidance.

If You’re a Curious Hobbyist

For the “I can do this, right?” crowd, the guide pushes into meaningful territory: tweaking print profiles, trying PETG or TPU, and adjusting supports. It gives me a vocabulary for what my printer is doing and why. Suddenly, I know the difference between under-extrusion and stringing. It’s like learning guitar chords; after a while, I can tell which one I mangled.

This is where it starts to get interesting, because small gains feel large. The book taught me that changing retraction settings can reduce stringing, that slowing down the first layer is not cowardly, and that a clean build plate is not a suggestion; it’s a lifestyle.

If You’re a Tinkerer or Small Business

For those of us flirting with utility—fixtures, prototypes, small-batch parts—the guide talks about consistency, not just possibility. It pushes toward calibration cubes, tolerance tests, and even inventory-friendly naming conventions for files. It suggests writing down your print profiles. The organizational vibe felt surprisingly adult.

There’s also a nod to serviceability: swapping nozzles, checking belts, and keeping spare parts. I learned how to listen to my printer the way a car owner listens for a new rattle. It made me feel responsible, in a good way.

Coverage of 3D Printers

The book covers the main printer families, focusing sensibly on what most people will buy: FDM (filament) and resin (SLA/DLP). I liked that it didn’t try to chase every exotic machine under the sun.

FDM vs. Resin: Sanity First

FDM prints by melting filament and drawing each layer with a moving hot end. It’s the bread-and-butter of hobbyists. Resin printing cures liquid resin with light to build layers and excels at tiny details. The guide gives me honest trade-offs: FDM is mess-free and sturdy, resin is stunning but requires gloves, ventilation, and more patience.

I appreciated the realistic advice on where each shines: FDM for brackets, enclosures, and household bits; resin for figurines, dental-like precision, and any object that would make a jeweler nod approvingly.

Material Guide: PLA, ABS, PETG, TPU, and Resin

I wanted a simple material map, and I got one. PLA is the schoolteacher of filaments—patient, forgiving, and unlikely to ruin your day. ABS is grumpy and needs an enclosed printer. PETG is like a gym trainer who thinks I can do a little more than I want to. TPU is a stretchy wonder but a little wild in the extruder. Resin is the fashion model: demanding, gorgeous, and worth it if you have the temperament.

The guide explained properties without turning it into a chemistry lecture. I now know that PETG likes higher temps and less fan, that PLA loves a clean first layer, and that TPU will test my patience if I try to print it fast. On resin, the book emphasizes safety. Gloves, eye protection, and proper disposal aren’t optional.

Hardware Setup: Bed Leveling, Extruders, Nozzles, Maintenance

This is the section that likely saved me the most time. The book walks me through manual and assisted bed leveling, explains why my “first layer squish” matters more than my horoscope, and argues persuasively that a clean nozzle prevents a thousand cuts.

I also learned the value of periodic checks: belts, pulleys, Z-offset, and whether my build plate is actually flat or just hoping for the best. There’s a rhythm to maintaining the machine, and the guide taught me the beat.

Coverage of 3D Modelling

Before this book, my modeling skills started and ended with dragging shapes around like a toddler arranging furniture. The book got me past that.

Software Introductions: Tinkercad, Fusion 360, Blender

The guide introduces several modeling options without trying to crown a king. Tinkercad is a friendly entry point for basic shapes and quick wins. Fusion 360 gives me parametric, dimensionally sensible models. Blender leans artistic and sculptural. I didn’t feel pressured—just informed.

What I liked most was the modeling mindset it offered: plan ahead. Think about tolerances and wall thickness from the start. It’s like cooking—season as you go, don’t dump the salt in at the end.

Modeling for Printability: Wall Thickness, Tolerances, Overhangs

I got clear rules of thumb: wall thickness generally above 0.8 mm for FDM, design overhangs with supports in mind, chamfer and fillet like a practical minimalist, and leave clearance for parts that slot together. It’s not strict doctrine, but it’s a reliable starting point.

This is where the book shines for beginners. It didn’t just tell me what a “manifold” mesh is. It showed me why a tiny hole in my model will destroy an hour of my life. It’s theory with mercy.

File Prep: STL/OBJ, Model Repairs, and Orientation

The book suggests common tools for checking and repairing meshes, and it explains the sins of bad STLs in nonjudgmental terms. It also tells me why orientation matters: strength, supports, aesthetics. If I want a smooth front, orient the model so the pretty side faces up, not down in a mess of scaffolding like a bat.

I came away with fewer mysteries. I don’t fear the “non-manifold edges detected” message quite as much. I still don’t like it, but I can see the path forward.

Coverage of 3D Plotting

The title promises “3D plotting,” and I admit I suspected marketing bravado. To its credit, the book actually explains it. It treats plotting as the path-based instructions for machines—like pen plotters and the toolpaths that drive CNC and printers. It applies the plotting concept to the broader workflow: from geometry to motion.

What the Book Means by Plotting

The book frames plotting as a way of thinking. Whether it’s a pen, a laser, or an extruder, you’re sending coordinates down a line. For me, this contextualized G-code in a satisfying way. Suddenly, supports and infill patterns weren’t mysterious—they were just patterns in a plot.

It doesn’t drown me in math. It gives me the big picture: slicing software converts my model into these paths, and correct settings influence how smooth, strong, or stringy those paths become.

Use Cases vs. Printers

Plotting makes a cameo in my thinking about choosing a machine. If I care about path fidelity at small scales—fine art, micro details—resin wins. For larger, utilitarian parts that don’t need microscopic polish, FDM steps in like a reliable friend with a pickup truck.

The guide makes that distinction clear in a way that anyone can understand, including me on a tired weeknight.

Slicing and Workflow

Slicing is where magic and mischief live. The book treats it as the control room, which is exactly how it felt once I started adjusting settings.

Cura and PrusaSlicer Basics

Cura and PrusaSlicer get sensible coverage. The guide walks through profiles, setting a good first layer, infill percentages, and the one area where I always overcompensate: supports. It nudges me toward restraint. Use tree supports where it makes sense, but don’t build a forest.

The guide reinforces the habit of previewing. I now watch the slicing preview like it’s a short film, looking for deep overhangs, missing walls, and doomed supports that touch nothing. It’s become a ritual, and I’m better for it.

Profiles, Supports, Infill, and Speed

There’s a nice structure to how the guide approaches profiles—I was encouraged to modify one setting at a time and document it. Infill percentages aren’t moral choices; they’re trade-offs. Speed is a knob, not a dare.

I appreciated the support tips: angle inclination, touching build plate vs. everywhere, density, and that joyful moment when a model is oriented so well that it needs almost none. The book doesn’t claim supports are evil. It just asks for purposeful use, which is a good rule for life.

Real-World Test I Ran Because of the Book

I decided to test the guide’s advice by doing what it told me to do: start simple, learn principles, and then reach a little further. I printed three projects:

• A cable clip (PLA, FDM)
• A minimalist phone stand (PETG, FDM)
• A tiny chess pawn (resin)

For the cable clip, I used PLA at 0.2 mm layer height, 15% infill, and a generous first-layer speed. I scrubbed the bed with isopropyl alcohol and set my Z-offset so the filament laid down like a tidy ribbon instead of a spaghetti tantrum. It came out neat. It fit my desk edge without persuasion from a hammer. I may have gloated.

The phone stand challenged me to adopt PETG. The guide warned me about PETG’s stickiness. It said reduce fan, increase nozzle temp, and consider an adhesion layer like glue stick so I’d be able to remove it without feeling like a medieval dentist. I did exactly that. There was slight stringing, but a quick pass with a heat gun cleaned it up. The stand holds my phone like a stoic butler. I’m proud of it.

The resin pawn was the showpiece. I followed the guide’s safety instructions like a person who wants to keep all their fingers. Nitrile gloves, decent ventilation, careful resin handling, and a sealed container for waste. I set the exposure time per the resin’s datasheet and let it cure post-print. It came out crisp. I painted it badly, but that’s on me. The layers were so fine I found myself squinting like a jeweler. This was the moment I understood the resin fanatics.

Safety and Responsibility

I’m not a risk-taker by nature, and the book’s safety section reads like a caring friend who wants me to have fun and keep my lungs. It wasn’t alarmist; it was practical.

Ventilation and Fumes

FDM fumes vary by material, and the guide suggests keeping rooms ventilated, especially for ABS. Resin printers demand more: good airflow, closed containers, and no wishful thinking with chemicals. I appreciated the clarity around filters and doors. A pro tip: being cautious is not uncool.

Post-Processing and Resin Handling

The book made post-processing straightforward: isopropyl alcohol baths for resin, curing times, and careful disposal of resin-contaminated materials. It also mentions the slightly meditative nature of support removal when you’re not rushing it. I resisted the urge to treat it like a raccoon going through compost.

Fire Safety and Common Sense

With heated beds and hot ends, the guide suggests basic fire safety: don’t leave printers unattended for long prints if you can help it, consider a smoke detector nearby, and keep the build area tidy. This is practical and seldom emphasized enough.

Common Problems and the Book’s Fixes

It turns out many disasters have common causes. The guide gives me a small toolkit for diagnosing issues. When a print fails now, I don’t feel personally attacked. I feel methodical.

Bed Adhesion and Warping

If it lifts, it left. The book suggests cleaning the bed, checking the Z-offset, upping the first-layer temperature, and using brim or raft where needed. It also suggests slowing down the first layer like I’m teaching it grace. Warping on large ABS parts? That’s an enclosure issue, not a printer betrayal.

Stringing, Blobbing, and Surface Quality

Stringing is retraction, temperature, or humidity. Blobs are often overextrusion or inconsistent flow. Surface lines show me either vibration or too-aggressive speed. The book gives me a plan, not a scolding.

Layer Shifts and Mechanical Gremlins

Layer shifts are the alarms my belt tension and pulleys set off. Cables catching, loose grub screws—these are fixable sins. The book encourages periodic checks, and now I do them with a small sense of ceremony.

Troubleshooting Table I Actually Used

Here’s the quick-reference table I ended up leaning on during my tests.

Problem	Book’s Likely Causes	Suggested Fixes	My Result
Poor first-layer adhesion	Dirty bed, wrong Z-offset, too fast	Clean bed with IPA, adjust Z-offset, slow first layer, raise first-layer temp	Fixed cable clip adhesion instantly
Warping on corners (FDM)	Material shrinkage, drafts	Use brim, increase bed temp, enclose printer or shield from drafts	Brim + higher bed temp reduced warping
Stringing between features	High temp, low retraction, wet filament	Lower nozzle temp, increase retraction distance/speed, dry filament	PETG stringing solved with temp + retraction
Blobs/zits on surface	Overextrusion, coasting off, retraction type	Calibrate flow, enable coasting/pressure advance if available	Smoothed surfaces on phone stand
Layer shifts mid-print	Loose belts, obstructions, high speed	Tighten belts, inspect cable routing, reduce speed	No more shifts on tall print
Resin print not adhering to plate	Underexposure, unlevel build plate	Level plate carefully, increase base layer exposure, ensure clean plate	Pawn adhered and printed cleanly

Where the Book Shines

For me, the book shines in three main areas:

• Clear sequencing: It teaches the entire arc without dumping me in any one section too long. I never felt stranded in jargon.
• Practical safety: It respects my health and home. Nothing kills a hobby faster than fumes and fear.
• Real-world calibration: It leans into calibration prints, slicer previews, and small tests. That “start simple” mantra saved me hours.

It also deserves credit for treating modeling as a skill anyone can learn. I didn’t feel like an imposter with a mouse. I felt like a beginner who could improve with predictable steps.

Where the Book Falls Short

Any “ultimate guide” has to make choices, and I felt a few gaps:

• Advanced tuning is only lightly covered. If you want pressure advance, linear advance, input shaper, and firmware tinkering, you’ll likely need supplementary resources.
• Resin post-processing could use more hands-on demonstrations, especially around supports and hollowing/vent holes for larger prints.
• The section on “3D plotting” is conceptually helpful, but if you’re expecting detailed pen plotter projects or CNC toolpath strategies, you may want to look elsewhere for depth.

None of these are deal-breakers, just boundaries. The book sets you up, but it doesn’t pretend to be a PhD in machine tweaking.

How It Compares to Other Resources I’ve Used

I’ve watched my share of late-night tutorial videos, usually starring a person who speaks extremely quickly while waving a caliper. The book wins on structure and sanity. It’s the teacher who lays out a semester, not a single enthusiastic lecture.

Compared to forums and Reddit threads, the book offers calm, curated advice without the chaos of twelve conflicting answers. There’s value in that kind of consistency. For deep, specific issues, the internet still rules, especially for particular printer models or obscure error codes. But this guide gives me enough insight to know what to search for next.

Value for Money

If the goal is to make 3D printing less scary and more successful, the guide delivers. It prevented several likely mistakes, which I can quantify in wasted filament costs and time I didn’t spend reprinting objects that looked like modern art in a bad way.

The real value is confidence. If you’re new, the book pays for itself in a weekend. If you’ve been printing a while, it’s still a tidy consolidation of best practices and a helpful nudge toward better workflows.

Who Should Buy It (and Who Should Skip It)

I love a clear recommendation, and here’s mine.

• Buy it if you’re just getting started and want a single resource to take you from zero to your first reliable prints.
• Buy it if you’ve done a few prints and want to stop guessing at slicer settings or material quirks.
• Buy it if you want to branch into resin safely and you prefer written guidance to a scattershot of videos.

Maybe skip it if you’re already deep into firmware mods, advanced kinematics, or you prefer learning exclusively by tinkering. It’s not that the book won’t help; it’s just that you might already be beyond what it covers with thoroughness.

Quick Coverage Matrix

Here’s a summary of how I’d rate the book’s coverage on key topics, based on my experience using it.

Topic	Coverage Quality	Depth Level	Notes
FDM printer setup and basics	Excellent	Beginner-Intermediate	Clear, practical, step-by-step
Resin printing setup and safety	Very Good	Beginner	Strong on safety; adequate on post-processing details
Slicing (Cura/PrusaSlicer)	Very Good	Intermediate	Good philosophy; missing some advanced tuning
Materials (PLA, ABS, PETG, TPU)	Very Good	Intermediate	Honest trade-offs; helpful starting parameters
3D modeling fundamentals	Good	Beginner	Solid primers; external study needed for mastery
Troubleshooting common problems	Excellent	Intermediate	Actionable, reasoned, and calm
3D plotting concepts	Good	Beginner	Conceptually useful; limited project-level depth
Advanced printer tuning	Fair	Advanced	Touches the surface; advanced users will supplement

Tips I Wish I Knew Before Printing (Inspired by the Book)

I learned more than I expected just by following the book’s simple advice. Here are the keepers:

• Always clean the build plate. If I skip this, the printer knows, and it punishes me.
• Lower the first-layer speed. Twenty millimeters per second can feel comically slow, but it works.
• Preview the G-code. It’s the closest thing to predicting the future that I’ll ever do honestly.
• Use brims liberally for tricky corners. Pride is not a structural material.
• Change one setting at a time and take notes. My future self is not as smart as present me imagines.
• Calibrate your flow rate for each filament. Don’t assume PLA is PLA across brands.
• Dry your filament. A few hours in a dryer can turn string soup into clean details.
• With resin, schedule the cleanup before you press print. The job isn’t done when the build plate rises; it’s done when the cured part is ready and the workspace is spotless.

The Writing Itself: Readability and Tone

I read a lot of manuals that sound like they’re written by robots for robots. This guide is better. It’s clear without being stiff, and it gives the right amount of storytelling to make lessons stick. I never felt lectured. I felt guided.

There’s a reassuring kindness to the tone. The book knows you’ll make mistakes and assumes you’re capable of fixing them. That combination keeps the process from feeling like a test I’m about to fail.

Mistakes I Made That the Book Prevented

I can measure this book by the disasters I avoided.

• I didn’t try ABS as my first filament. This spared me a foggy room and a warped hexagon.
• I didn’t crank print speed like I was trying to win a race against boredom.
• I didn’t skip leveling the bed after moving the printer. I leveled, and parts stuck like loyal friends.
• I didn’t rip supports off resin prints before they were fully cured, which would have left fingerprints like I fell asleep on a lacquered table.

It turns out a few simple habits keep me from most calamities. The book pushed those habits without shaming me into compliance.

Project Ideas I Got from the Book

I like practical prints that solve small annoyances, and the book gently nudged me toward them instead of the one big, ambitious project that gathers dust. I started with:

• A drawer organizer with slots sized to my favorite pens
• A set of cable clips that give my desk back its dignity
• A toothbrush holder that actually fits the wide-handled brush I like
• A resin mini that looks better than anything I could paint
• Replacement feet for a wobbly kitchen gadget

These are small victories, but they build the muscle. After a few successes, I felt confident enough to attempt a functional hinge with tolerances that actually mattered. It worked on the second try, which felt like a personal holiday.

What I Wish It Had Explained More

If I got a chance to request a second edition wish list, I’d add:

• A deeper walkthrough of pressure advance and input shaping for compatible printers
• A more detailed resin support strategy for complex geometries
• A stronger treatment of tolerances with examples for common fittings (M3 bolts, snap-fit designs, press fits)

None of these are showstoppers, but they’re the kinds of topics I found myself chasing across forums. The book got me 80% of the way, and I wanted the last 20% tied up with a bow.

The Emotional Arc of a Print (And Why This Book Helps)

I noticed the emotional stages of 3D printing look like a soap opera: excitement, fear, doubt, cautious optimism, surprise, pride, and sometimes quiet despair. This book doesn’t skip to the end. It sits with me in each stage and says the useful things: slow the first layer, trust your profile, watch the preview, and don’t yank at supports like you’re extracting a tooth.

I started to enjoy the process because I understood it. When a print fails now, I look at it like a detective, not a victim. That shift is more valuable than any single trick.

What Makes It “Ultimate,” Really

I had a reflex to roll my eyes at the word “ultimate” in the title, and yet, as far as a single guide goes, it does a lot of heavy lifting. It gives a newcomer a full runway and still feeds a hobbyist with good practice. It hops across printers, modeling, slicing, safety, and troubleshooting without getting stuck.

Is it truly ultimate? Only in the sense that it aims broadly and lands many punches. The “ultimate” version of anything changes quickly in a field this active, but this guide earns its ambition by being useful today and teaching principles that remain useful tomorrow.

Little Details I Appreciated

• It reminds me to measure the room temperature for materials prone to warping.
• It encourages me to consider the environment—via ventilation and proper disposal—without grandstanding.
• It assumes I might want pretty things (resin) and sturdy things (FDM) and lets me have both without guilt.
• It doesn’t pretend advanced slicing profiles are “set and forget.” It treats them like recipes I’ll tweak to my taste.

These touches add up to a resource that feels like it was written by a person who has actually wrestled a stubborn print off a build plate at midnight.

If You’re Buying a Printer Because of This Book

The book doesn’t push me to any specific brand, and I won’t either. But I took away a few sanity-saving criteria:

• For FDM: look for a printer with good community support, easy bed leveling (assisted is a plus), a direct drive extruder if you plan to try TPU, and readily available spare parts.
• For resin: consider a machine with a decent build volume for your goals, an easily cleanable vat, and a screen you can replace without a meltdown.

It’s less about a shiny spec and more about living with the machine. The guide nudged me toward that kind of thinking.

Maintenance Habits That Actually Work

The maintenance advice in the book is shockingly doable, and I say this as a person with a checkered history of ignoring warnings on labels.

• Wipe the build plate and re-level when prints start acting moody.
• Keep a small log of changes: nozzle size, filament brand, profile tweaks.
• Inspect belts and wheels monthly. It takes minutes and prevents heartbreak.
• For resin, strain the resin between prints and keep the vat free of cured bits.

I have adopted these like a reluctant but grateful adult, and my prints are better for it.

If You Already Model in 2D or 3D

The book respects people coming from design backgrounds. If you already use Adobe tools or CAD, you’ll adapt quickly to the constraints. The guidance on tolerances and print orientation will be your biggest leap. I liked that it didn’t force one software on me; it said, “Pick a lane you enjoy, then learn just enough about the others to be dangerous.”

I found Blender’s sculpting intriguing for resin minis, while Fusion 360’s constraints made my functional prints behave. The book prepared me for both without picking a favorite child.

Small Joys and Aggravations the Book Prepared Me For

There’s a special joy in removing supports cleanly and seeing a smooth surface you didn’t quite expect. There’s also a unique frustration in a 95% complete print that fails because the last layer turned into angel hair. The book prepared me for both.

It lowered the stakes by making experiments smaller and giving me exit ramps when something looked off. It turns out the best way to avoid heartbreak is to stop thinking that I’ll nail it on the first try.

My Final Test: Can I Recommend It Without Caveats?

I can, with the gentle caveats I’ve already mentioned. As a foundational guide, it’s excellent. As a one-stop shop for advanced tuning or deep project specificity, it’s necessarily limited. But I don’t want a single book to do everything. I want it to do the first 80% so well that the remaining 20% feels like a hobby, not a homework assignment.

This one does that.

Final Verdict

I came to “3D Printing: The Ultimate 3D Printing Guide! (3D Printers, 3D Modelling, 3D Plotting) (3D Printing, 3D Printers, 3D Modelling, 3D Plotting)” hoping it would make me feel less like a trespasser in a technical forest. I left feeling like I had a map, a compass, and a headlamp that didn’t flicker at the wrong moment. I printed a cable clip, a phone stand, and a small pawn, and none of them embarrassed me. That feels like a clean win.

The book’s greatest success is how it trades panic for process. It makes safe practices second nature, gives me a rational approach to settings, and treats my mistakes as steps rather than verdicts. If you want a guide that makes you productive faster and keeps you curious longer, I recommend it.

And if a print fails in the middle of the night, you’ll know what to do: clean the bed, slow the first layer, take a breath, and try again. I learned that here, and I’m oddly grateful.

Disclosure: As an Amazon Associate, I earn from qualifying purchases.