Someone else pointed this out but RSI's can happen and fast and BAD.
And I know some of you will say "that doesn't happen to me. It won't happen if you stretch and do this or that" that's *YOUR* body. Other people can do all that and it STILL HAPPENS.
For the love of Kirby please do not listen to anyone who says you should be doing two finished pages of comic book art a day. It is a recipe for burnout, misery, and eventually, the destruction of your career.
Industry standard is one a day, five a week. Period. Got it?