Well, I haven't yet posted any fanfics here yet, but I'm a member of a couple of fantasy roleplays on a couple of other forums. As such, I feel fairly experienced as a writer; in one of those RPs I'm consistently able to do more with my single character than the other members do with their two, three, or five.
However, I never feel the need to ask someone to edit one of my stories. I might throw an idea out (in my circle of HONEST friends) and see what they think, but I do all of the writing on my own. I'm pretty good at catching my own mistakes through proofreading; I tend to read even my regular posts a number of times over for errors. As for the overall content...well, I've been writing pretty actively for close to three and a half years now. I think I know what aspects of writing I really need to work on.