As an editor, I echo the suggestions for quality editing and beta readers prior to publication. As a writer, I know it takes more than one set of eyes to catch, not only grammatical mistakes, but content issues. Every editor has blind spots–mine being the bottom of the page. Every writer is often too blinded by their shimmering words to see their glaring own errors. That’s why this editor-writer plans to rely on the eyes of others rather than only her own myopic ones.

http://www.selfpublishingreview.com/2014/05/why-hiring-an-editor-for-your-book-is-unavoidable/