The person you can rely the most is always yourself, and while some gamblers look for external sources to help them to manage their money and prevent them to spend too much of it in gambling, the truth is that no external source can help you for long as a gambler that has taken the decision to keep gambling will always find a way to do it, so if a person wants to control their gambling, they have no other way than to try to do this on their own.
No doubt except a gambler wants to be responsible with his gambler it will be difficult to help him but implying that no external source do not play big role in helping a gambler can be misleading. The efficacy of an external source lies in the acceptance of the gambler that he is willing to bet responsibly if he is helped. When such confession is made the external forces can play it's role. Understand that the external force is not there to help a gambler forever. The external force will only come him to help the gambler return to normal and responsible gambling. When this is achieved a gambler can be allowed to control himself.
Personally, I think the bet way to manage a gambler is to instill responsible gambling practice in him the moment he starts gambling. I want to call on all bookies to include in there term and conditions responsible gambling practices so that as an individual signs in he is directed to read the practices. This can go a long way in ensuring that individuals gamble responsibly. Merely saying "bet responsibly" is not enough because what constitutes a responsible gambling made not be known to a new gambler.