As the questions says, when do you stop? your point of no return?
a. at least double your money, then stop
b. you only stop when you have lost all your bankroll money and then blame the casino?
c. or you are a superstitions gambler, when you have signs like losing 3 straight in a row, then you quit because you know that you're having a bad luck
d. you stop when you are at least break even
I didn't include chasing your losses as obviously you might to continue.
What determines when I stop gambling and quit for the day is not included in your options, the major thing that determines when I stop gambling is when my budgeted bankroll is exhausted. When this happens I don't think twice about stoping and exit, I've trained myself for it and it has been very effective. I don't continue to gamble because I'm winning or losing, I center my exit plan on my budgeted bankroll for the day. I will rather exit before exhausting my bankroll than go beyond it. I actually trained my mind to be disciplined about gambling because I know that it's disadvantages are very negative.