Being able to edit your own work is a skill I think every writer should develop. Never mind the fact that I don't like paying for anything I can do (and should do, IMHO) myself.
But, if you're looking to doing the self-publishing route, that changes things simply because it's always best to have another set of eyes (trained eyes, for that matter) look over something. A commercial publisher provides that in the form of the editing team, but if you're the publisher, you'll need that extra set of eyeballs.