I'm constantly surprised by the errors that plague many manuscripts and documents I edit. I often wonder if the writer has bothered to review the work before sending it out. I recently mentioned a technical document I edited that was in rough shape. Clearly, the writers did not go back and read over the document because if they had, they would have fixed the dozens of spelling mistakes, completed unfinished sentences and ideas, and would have known material was in places that made no logical sense.
I am fairly certain most writers don't read over their work, and it's mostly because they are done with it, had enough. I know. I write and you get to a point where you can't stomach to read it or you are so tired of the project you simply want to pass it on - and off.
But don't, dear reader. Put it aside for a day, a week, a month - whatever you can afford. Then return to it with a fresh perspective. When you do, you'll see the flaws, gaps, and errors and will be in a better state of mind to fix them.
Don't release unfinished work, even if it's going to an editor. If you can get it in as good a shape as you can, the editor spends less time on minor things (like spelling) and can focus on the big picture. Oh. And less time with the editor = less money out of your pocket. You know what they say - time is money.