From a money making point of view the only criterion for playing is whether you’re a favorite in the game or an underdog. If you’re a significant favorite, then it’s a good game, and you should stay in it; if you’re an underdog, then it’s a bad game which you should quit. Never quit a good game as a small winner just to ensure a winning session. By the same token, don’t continue playing in a bad game just to get even.
Many players don’t follow this precept, however obvious it may seem. They play as though they want to win the pot, an individual pot, at all costs. The worst of them, to put it bluntly, are the suckers in the game. On the other hand, a good player develops the patience to wait for the right situations to play a pot and develops the discipline to release a hand he judges to be second-best. Similarly, you should not allow the fact that you are winning or losing to affect your decision to stay in or quit a game.
Even for tough professionals, quitting a game, particularly when they’re stuck — that is, when they’ve lost money — is sometimes a hard thing to do. So long as you remain a big favorite, you should stay, even if it means using toothpicks to prop up your eyelids. But if the game has changed so that you’re an underdog, you should quit whether you’re a winner or loser. When you’re stuck, you should examine the reasons why you’re stuck. It may be just bad luck, but it may not.