Student here. What size artboards do people use? If I'm designing a business card, is the idea that you make the artboard the exact same size as the card. Or do you leave a bit of room on the edge.
If your project needs bleeding, you can prepare your document with the bleeding. If you need to prepare a template to print 10 business cards, to be printed on an A4 size paper, you prepare an A4 artboard.
You prepare the artboards as you need them.
Some programs will add the bleeding outside your artboard, or even cutlines. But if you know how to deal with them, you can add yours yourself.
It's really doesn't matter. Whatever works for you.
Artboard sizes can always be changed when needed.
For Illustration, which is unrelated to any direct stock/paper size, I tend to start with 649x649pts - or 9x9". No real reason other than it's a decent size to see things as I work.
If this business card goes to print, in most cases the artboard needs to be exactly the specific size of the actual card. Plus bleed on the sides, if the printer requires bleed.
If you're not printing it, and just doing a simulation, presentation, variations, etc ... then the artboard size is not that important, you can use a full page size artboard (US letter, A4, etc).