How about a classical musician viewpoint? I have an uncle who is a concert pianist. He has played all over the world, with symphony orchestras, solo performances, and clinics. As he's nearing 80 years old, and retired as Chair of the Piano Dept at Penn State, he has scaled back on his concerts.....but prior to all that, he would practice five to eight hours per day, and even more if schedule allowed, and especially if he had a concert coming up. My personal practice time is probably 2-3 hours a day, with 1-2 spent learning new material, and 1-2 spent reviewing stuff I know to keep my chops and muscle memory up. And, I'm nowhere near a "working" artist's level.