Running through the scales
OMG, I've layed off so long I can't run through the scales on the keys anymore! I could just lay off for however long, and come back, and start practicing again, running through the majors and minors, at least. From all that work as a kid. It was so easy to come back, it was like a "ride the bicycle thing".
Crap. Don't ever stop practicing. At least a little bit.