In my own experience, to know how to stop while playing gambling, you should know first to limit yourself or you should have a self control for you to have a less chance to lose a lot of money in gambling and more earnings. Being greedy in playing gambling should ve avoided because if you are greedy it is very hard for you to stop playing.
The limit is not something that we have from our within but it is something that we set to put out the limit that we can pull. If we set our limit smaller than what we could have managed that means we are saving ourselves from losing more than what we expect. It is better to do so because the more we gamble, it will means the more we lose