I like to know your opinion about the question because I believe every gambler has a different way of managing himself.
My answer to the question is I can easily stop when I am winning because I am afraid I might end up with nothing since I know to myself that I am not yet consistent enough to win in gambling, however, based on my experience, I can't easily stop when I am losing despite the fact that I already set up a limit to gamble in a certain day or a certain session.
Do we have the same attitude or not?
Don't be greedy and handle your funds wisely and you don't have to make such decisions hard. We all know that gambling couldn't guarantee us an assurance of gaining a good profit all the time so we should accept the fact that there will always be losses along the way so we have to know our limits.
If we know how to handle our funds, we will know when to stop and when to take the risks. It all goes with self-discipline.