"A woodpecker can tap 20 times on a thousand trees and get nothing, but stay busy. Or he can tap 20,000 times on one tree and get dinner."
—Seth Godin from "The Dip"
Don't let this happen to you when you are practicing your instrument, working on your conducting, or pursuing whatever it is that you do.
Don't start working on something and then stop when it gets difficult to move on to something else.
There is a potential trap there. If you move along to work on something else you can trick yourself by "staying busy" or "working hard" or whatever euphemism you'd like to use instead of calling it what it is: that you bailed once the work got difficult.
The successful people in the music business regularly try the 20,000 times thing and then eat dinner.
What are you avoiding by moving on to the next tree well before you reach 20,000 taps?