If the person is having a problem with addiction then they must try to understand the reason why they are addicted. Many people gamble for fun and not for earning money. If that is kept within limits then its not bad, however if they gamble for money and then they continue just to chase losses then its bad. One must control that type of habits which makes them lose money unnecessarily. Rather live happily on what you earn.
When people go gambling without any limit then after some time giving up gambling will be completely impossible for them. So, keeping some limit from the beginning itself will be the only solution to give up gambling at any time.