So in the GTD system, an action can be a permanent, do-every-day thing? How would you decide it's "done" then? (assuming lots of long-term goals require "practice x for y/times per z" events)
You may pick a piece you want to play of modest complexity and difficulty. You're "done" when you can play it. But are you really? No, you just pick another, harder, piece.
The practice is to get you to that skill level. If you simply enjoy playing, you may never be done. But you know that each day you have allocated 30 minutes or so to practice.
