i think it is not such an easy job to quit gambling and if you are addict of gambling , as i have seen so may people who have stopped gambling but then start it again after some time.
it is not that easy so if it's possible the best thing to do is not to get addicted in the first place by implementing self control while you still can because when you get addicted to gambling, it's almost impossible to quit as you're going to be thinking of it most of the time and the urge to continue would be stronger the more time you try to avoid playing
Yeah, you're correct prevention is better than cure. if one gets addicted then it'll be hard to stop, an addicted gamblers can/will lose all of his money.(if he doesn't quits early)