I know there are a bunch of answers to this question “over yonder” and thought I’d ask here instead. The more exhaustive the checklist, the better.
Edited to add: I am likely getting a medium breed, possibly a smaller breed. I am asking for a checklist of things to purchase ahead of time, and not tips (though I thank those who did offer tips). This would be things like a crate, food/water bowls, etc
Get bitter apple spray for chewing and handle paws, teeth, gums, belly, tail when young. My dog is defensive when nail clipping and it is obnoxious. Keep high value treats on hand and start training as early as you can.
That’s what I wish I did when my dog was a puppy.