[gabemart]

I don't make a hobby out of editing, but when I'm reading an article in a field I know a little about and I come across an egregious error, I usually edit it, or leave an edit request if the page is protected.

I do the same thing for articles outside my areas of knowledge if the error is particularly galling and unambiguously incorrect.

Because I use wikipedia quite a lot, I'd say I leave an edit about twice a month.

Having said that, much, much more often I encounter a minor error that I don't have the time to investigate. In this kind of case I think "boy, I bet the source doesn't actually back that up", but it doesn't seem important enough to break my workflow to look into.