Every week or even everyday is fine as long as you stay on your own limit on each play. It is better than you play once a month or even once a year but you play over your own limit. They key is your own limit and yourself, no matter how often you play, as long as you stays on your limit then it wont be bad thing for you.
But it is really hard. Putting a limit to yourself means that you are being conscious of your self getting sucked in on gambling and you need to stop yourself before something happen bad. But when you are already having the interest on gambling, even if you put a limit, it is still hard to get out of casinos. I think it is really best to get a help even if you think that it is not that bad. It is better if you get a help earlier.