You have a masterpiece all completed. It is a work of art. Until you have it in your hands in printed form and you start reading. There are mistakes all over the place. Misspelled words... How can that happen when you you spellchecked three times? What happened to that quirky character that in your writing seemed so funny and added so much spice? In the printed version, he comes off as lame and abrasive with no compassion. But what can you do? The book is in print, and that self-publishing company is going to charge you for making so many changes!
We need to rewind to the time before that manuscript ever left to brave the world.
Think of an editor as Coco Chanel or Christian Dior of the publishing world. But you don't have to pay fashion designer prices to get fashion designer quality in your writing. The investment in the right editing has a very high return of investment because you become a better writer. After you see the suggested corrections, and see how much better your work is, you can skillfully incorporate those changes and even apply them to your next work of art. That makes you a better writer.
Your work is a masterpiece because no one else could have told the story exactly the way you have. No one else thought of the story, or studied the subject like you did for that article. Yet, the clothes your work is wearing are not fashion designer quality. They are definitely serviceable, and enduring, but sending your work out into the world without dressing it up to the nines reflects badly on you and can tarnish your reputation.
In choosing an editor, everything depends upon what kind of editing you need. Every solid piece of writing can be tweaked and trimmed into excellent writing. An author is too close to the work to be able to see the whole clearly. An author needs to be married to the idea, but not to the words. A professional can give you on the job training in how to write more clearly, how to use active voice instead of passive voice, how to develop your characters into vibrant, lifelike humans instead of caricatures. Your work will be like a river with white water rapids and still water depths.
How to choose an editor?
I completely understand about the sample edit thing. Five pages is hardly enough to display the skill of an editor, but it takes so much time to edit some things because of many reasons: a) the author has English as a second language; b) the author does not have the work perfected to be ready for a comprehensive edit because the author wants the work "cleaned up" so more writing can be done (as in only a first draft is complete; c) the author has no clue where the story is going; and d) the author does not know what kind of editing he/she needs.
I never knew that I was such a bad proofreader until I had a professional proofreader edit one of my books. I thought I had done a really good job proofing the thing. I received back a gold mine of corrections that saved me a lot of embarrassment because I self-pubbed that book. I am truly proud to market my book because I know it is a professional presentation of my thoughts and studies. That is priceless. I also realized that I was far too close to the work. My words were my deepest thoughts so I didn't realize I had so many common errors that writers make until I saw them highlighted by my worthy proofreader.
Another excellent benefit from having your work professionally edited is that it makes the author a better writer. There are many people out there with Bachelor's and Master's degrees who still can't put a really good fiction book together. An editor can see the big picture. An editor is far enough away from the author's work (both fiction and non-fiction) to identify the holes in story or thesis, give great advice on characterizations, make sure that dialogue is snappy and character-unique instead of all characters talking the same (as I've read many books with this problem).
What an author needs is more value-realizing of the great investment that editing is.
