and I am sure you knows when time to stop or continues. If do not have a target you don't have the goal.
For a theoretical or target for a gambler just have a little affect, he will be aware of when to stop when he suffers defeat and loss. But after the next few days if a gambler have money he will gamble again, and the cycle will take place. The best way to stop gambling addiction, you have to leave your habits for example leave the same friend of the gambler because the environment will shape yourself, you can be friends with a group of people who are not gamblers, find a new atmosphere leave a place that you think will return to gamble.