I think it depends on what you view as "paying dividends". One dividend is enjoyment: are you enjoying the time you're putting in? That's typically easier with a well-asked question.
Another might be skills learned: are you picking up new techniques, new approaches by solving someone else's problem? Are you improving your communication skills?
Another might be the dividend to the world: is your answer making the world a better place, not just for the person who asked the question but others who may be facing the same problem?
And yes, there's rep. A number on a server somewhere. Don't pay that too much attention :) There are effective ways to rack up rep points that don't accomplish anything else nearly as worthwhile. My advice is not to go there. Focus on things that matter, and typically the rep will come as a side-effect, at least in many cases.