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.
Stopping gambling is a hard decision that a gambler could make. It is a strong decision made by the gambler, and none of those things you have mentioned, OP, can urge a gambler to stop.
Honestly, I could only stop if I saw that gambling made no sense for me. Or like I see gambling as nothing and boring. But until I enjoy doing it, and despite losses, I know I'm still gambling.
Don't try to gamble if you already think about quitting soon. Why? because that's even difficult to get out when you're there.