When you are affecting your personal life or others people life then you should know it is time to stop what you are doing and think about it. If you are just gambling for fun and to relax, gambling can be just a game if it is at your comfortable level expenses but over stretch your savings it becomes a big problem and you should start to do something about it.
It doesn't the scale for a gambler to know that it is the time to stop when others are already affected with your hobby or addiction in playing. On before it happened then you should be mindful with the things that it will happen if you did not stop your playing activity,
I think that we should not even start and if we do not start then there will be no need to stop gambling, because gambling is bad habit and those who gamble will ruin their future. If someone gambles for fun he should stop when he knows that now the limit has come and I dont have enough money to gamble anymore. This is the right time for quitting gambling.