Sometimes people overdo the idea of quitting and how awful it is. “A winner never quits, a quitter never wins.” That’s a catchy line, but catchy lines are not to be taken 100% literally all the time.
If you are fourteenth man on your team, never getting in the games, and you have a chance to get on another team where you will get to play, quit. If you don’t like the sound of the word, tell the coach politely that you are “dropping off” or “changing” teams. There is nothing wrong with quitting when you are merely making an intelligent choice for a better use of your time.
However, when quitting involves not a better use of your time but merely a poorer use, then quitting is bad. A poorer use of your time is when your team gets behind, and you are still playing, but it is obvious that you have quit trying to win, you have quit hustling, you have quit playing with enthusiasm, and you have quit giving your best effort. There is no excuse for giving less than your best in practice, in games, in any circumstance. Learn to give your best routinely, and don’t quit doing your best regardless of what those around you are doing.
Quitting when there is a better alternative (like going home to work on ball handling drills instead of remaining in a pickup game where no one is trying hard) is intelligent and should not be confused with quitting-but-still-going-through-the-motions.
From Dick’s book Stuff
Welcome To Keys To The Gym 
This is great advice…more practical and realistic than the oversimplified “never quit under any circumstances” you often get.
Much agreed Bill. It is more logical too. I think it is all too easy to let ultimatums like “never quit” over ride common sense. I feel like the energy behind so much of what Dick wrote was calling us to think for ourselves and know why we are doing something, and even if that is with quitting, if we think it through we are making more intelligent decisions.