I only stop if ever i had lost my balance and keep coming back after a week. Im still trying and hoping that one day ill win big thats what keep me from coming back.
Of course if you don't have any balance in your bankroll, even if you like to stay you can't do it anyway. That's why they come back most of the time in the gambling site to play around again. Maybe it is their adrenaline for them to come back in the games.