He's learning 3 instruments and follows fairly strict/non-negotiable routine for practice on each. (He has to be organised to fit it all in.)
This week he has school show (We Will Rock You), including rehearsals 9-4 today and tomorrow, dress rehearsals on Monday and performances Tues-Thurs evenings.
So I agreed a week off music practice completely Sat-Thurs.
What does he do when he gets home today? Sits and potters on the piano for half an hour or so, sight-reading some Queen numbers and generally tinkling just for fun! If I'd suggested he do some piano practice, he'd have thrown a strop. 