I’ve been fortunate to have toured with lots of authors and I was always fascinated with how they wrote. How they created stories, and characters, and pulled together the information for their books. The one constant that came from these discussions was the fact that self-editing is a very slippery slope.
Authors have told me time and again that going back to correct the little things in your writing is a never ending process. The manuscript will never be as good as you want. That is why you need an editor, someone who can help you with the process of laying the manuscript out in a logical sequence, help with character or story development.
If you’ve never worked with a true professional, then you need one. Editors help writers establish their voice and improve their writing, self-editing is a long road that never ends.