On some Summer days, I looked forward to practicing the bass. While I had some exercises to go over for the next week's bass lesson, the pressure of the school year was absent. I didn't have to practice any music for school ensembles or outside-of-school ensembles, so it was satisfying to sometimes play pieces I already knew well. Granted, I didn't expect to learn anything by playing pieces I knew backwards and forwards, but once you reach a certain level, you should be able to play your favorite pieces now and then.
After all, musicians ought to be able to play for enjoyment, not just to fulfill assignments.