1) To have discipline in life
2) Self control that only this amount to be played if lost, then you will leave the casino
3) Not to borrow any money from any one
It depends on a person though, following this rules might just lower the risk of losing too much money and not really want to quit gambling. Gambling is not that easy to quit if it becomes a habit, because no matter what you do, it is just feel that your day is incomplete without you doing it, so there is no way to quit just like that.
It is like you are trying to forget someone you knew even though you know you cannot, but if you are really dedicated to do so, then you can do it, just don't fool your own self with your promises.
Yeah if you want to quit gambling then you need to divert yourself towards some other hobbies and that will help you in giving up gambling but if you are addicted to gambling then it will become very hard to quit it and you will keep on coming back again and again.