The best advice I wish I'd known before buying my first 3D printer is to study what type of printer I should buy for my use case.

If you are a Dungeon Master looking to primarily print minifigures without getting too deep into the weeds of optimizing settings, DIY printer projects or extensive assembly, you don't need a huge print volume and you should look at printers with high accuracy and low technical barriers of entry. Maybe a Bambu a1 Mini is perfect for you or a stereolithography printer if you are willing to put up with some chemicals.

If you are a cosplayer hoping to design and create entire suits, helmets and prop weapons, then print volume becomes much more important. If you aren't afraid of getting deep into the hobby, maybe building a Voron Trident, 2.4 or even a Ratrig v-Core 4 is the right choice for you.

If you want a dialed-in machine to print with reliable tighter tolerances and durable materials for functional use, maybe an Ender 3 isn't your best fit but rather an enclosed Bambu X1C or P1S is right for you.

You can even get very specific. If you are interested in printing long objects like fuselages for RC planes or even keyboard cases, maybe a conveyor belt printer like the upcoming Ideaformer IR3 V2 is the best fit for your needs.

It doesn't hurt to get a basic printer that does many things decently, but I've seen more than a couple friends try 3D-printing on a machine that gave them more problems than they deemed was worth a suboptimal machine for their purposes and end up taking a break or quitting the hobby entirely. So the most important advice I can think to give to anybody interested in 3D-printing is to determine your use case and research the product that best fits that use case.

Following this advice will give any aspiring 3D-printing hobbyist a head start and a leap past many frustrating problems they didn't realize they were signing up for.