It varies between people. I never have to change mine, but I have a light touch and don’t use paper like screen protectors. What you should watch for is visible wear (unless you rotate your pen it will probably be uneven wear) and/or pen pressure feeling wonky.

I hated that about so many studio classes I took. Especially when it was a medium I’d never used before. Apparently we were supposed to intuit technique and skills lol Why take a class then?

It’s definitely the most relaxing for me as well, though I bet most artists find their favorite parts more relaxing than the rest