How often do you have to submit a post?
Post how often?
There's really no set minumum of how much you have to post. Just, make long meaningful posts that contribute to the topic(s) and have your own opinions, don't just quote somebody for the sake of posting and earning points. Really, just be active and post a few times a week. That's what I do. Keep your points above 0 is all you really need to do to keep your hosting. 
