What Do You Need Editors For?

I've been asked the question many times, almost always by non-writers. Or if the question comes from a writer it is, for certain, from one who hasn't yet been published. "What do you need editors for? What right does anyone have to tell you how you should write your story?"

The best analogy I can think of as to why writers need editors is that it's the same as singers relying on vocal coaches throughout their careers, however stellar those careers may be. Why? Because they need someone to...