Some of them are gifts, not purchases, but that wouldn't make as catchy a title. Either way, they sure are the best.
4K monitor
Videos and video games aside, the thing that truly sells 4K to me is fonts. This glyph rendering is incredible. No amount of antialiasing or bullshit like subpixel rendering can compare to having 4 times as many pixels. Considering I can't tell those pixels apart, this resolution is comparable to printed books for me - something people in the '80s could only dream of when they conceived the idea of WYSIWYG. Needless to say, I'm not going back.
Epilator
My legs have been cursed with thick and dense hair that's impossible to shave. You can try, but it regrows in a matter of literal hours, turning into an irritated bloody mess in the process. I've always suspected that an epilator could fix this, and guess what, I was right. It absolutely did - it takes the hair a couple weeks, not hours, to regrow now, and even then it's not as thick.
If you're thinking about buying yourself one, here are some tips: First of all, yes it is painful, but it gets less painful when hair is not as dense. Unless you wait, like, a month for it to regrow completely, your second time won't be nearly as painful. For your first time, the trick is to go slowly, as slow as you can, and put up with the unbearable pain. It may take forever, but going one row of hairs at a time is better than experiencing pain that's even less bearable.
Fingerless gloves
I hate wearing gloves. They limit my fine motor skills, so I have to either constantly take them off or suffer each time I want to take my keys or money out of the pocket. They also don't work with touchscreens, and I know I'm not supposed to use my phone while walking, especially when it's cold outside, but fuck you, I'm gonna do it anyway.
My hands hate the cold. Every time the temperature drops below, like, 10°C, they turn into a red dry desert that only spreads farther and gets drier and redder the more I go outside. When it gets real bad, they start bleeding. The problem doesn't completely go away until it's warm outside again, no matter how much moisturizer I use.
Did I, at some point, consider these facts, accept that wearing gloves is a necessity for survival, and go on with my life? No, of course not. Instead, I did nothing up until this year when I realized that fingerless gloves have none of the issues of regular gloves and are almost as good at keeping my hands warm. Once in a while, being a stubborn idiot has its upsides.
Kitchen scale
I've recently gotten into cooking, and having a scale has been a lifesaver, even more so than measuring spoons or a measuring cup. I'm notoriously bad at eyeballing things, so if I don't have a concrete measurement of something, I can and do mess it up. But not anymore - my inconsistent hands now manage to consistently make identical pizza dough each time I try. All I needed was a mass produced piece of equipment you can buy for $5 and actually bothering to write down the recipes.
Microwave
I grew up in a household without a microwave. I don't know why we didn't have one because it's an awesome tool for reheating and unfreezing food. Additionally, it's more reliable and requires a lot less effort when it comes to boiling macaroni and grains, which is a good thing because I'm really lazy. It's a shame it took me so long to discover that, but at least I know why I shouldn't repeat my parents' mistake.
Reusable shopping bag
Plastic bags suck. They're harmful for the environment, cost a lot of money to buy each time you go shopping, and are practically not reusable. You use them a couple times, and they already start falling apart. You can use them as glorified trash bags, I guess, if you don't mind the price, but why would you? I wish I'd been asked this question before because it took me way too long to realize that I could buy a real shopping bag, made out of cloth, and forget about ever dealing with plastic bags again.
Plastic bathroom drawer
Okay, that's a weird one. I understand this is a very specific problem that most people likely don't have, but I struggle with doing things that don't have one obvious order of steps. One of these things is my morning routine.
I've tried hard to stick to a specific order but couldn't until I bought a plastic storage thingy with 3 drawers in it. I put the stuff I need for brushing my teeth on the top, the stuff I need for shaving in the middle, the stuff I need for skincare on the bottom, and the whole thing in my bathroom. The issue is no more - I go from top to bottom, no thinking required.
Scarf
This is a story similar to the one with gloves. I have an utterly dysfunctional immune system, so I get sick all the time. Does this mean I've always worn a scarf to protect my neck and not get sick even more often? Nope! Not only did I not learn how to wear one, I'd never bothered to get one in the first place until last year. Sometimes, I'm surprised that I'm still alive in spite of my recklessness.
Xiaomi Redmi Note 8
Before we get to the praise, there's one thing you need to keep in mind: Xiaomi is not your friend. It's a company whose primary business is selling you a shitty Android reskin with an extensive history of spyware built into it, that they don't want you to get rid of, making you jump through hoops of increasing insanity to unlock the bootloader and taking their sweet fucking time to release the kernel source code and comply with GNU GPL.
With that said however, their hardware is pretty damn good for its price. My Redmi Note 8 was $150 when I bought it, and it's been the most reliable phone I've ever had so far. There's a rich custom ROM ecosystem, so I'm able to run a somewhat maintained copy of Android 14, with all of the useless crap cut out, even though it's been 5 years since the initial release.
It's also worth pointing out that the camera in this phone is outstanding - as long as you disable edge enhancement, which you should as it's the worst thing that's ever happened to photography, it performs as well as early 2000s digital camera, except it fits in your pocket and can record video in a non-potato resolution. The battery is just as great and lasts long enough for it not to be annoying. That is unless your ROM gets a mysterious battery drain issue which has happened to me once.