I'm working on the seventh draft of the book I wrote last year. I believe I only have to make major changes in the early portions of the book, but those early portions go on and on. I'm having big problems linking bits and getting from A to B. I'm sometimes only able to struggle through a page a day, or even less.
And I've only had one reader for this manuscript. With this draft, I'm responding to a couple of her suggestions that I felt were very appropriate. So, seven drafts with only one reader. If this ever gets picked up by a publisher, we could easily end up with a total of ten drafts or more.
I've always felt that writing becomes more and more difficult the more drafts you do because after a while the well runs dry. Where will the new material come from? After the experience of writing this book, I'm beginning to think that there are limitless things you can do with plot and character. You may have to dig them out of your own internal organs, but they're there.
In fact, it's a little frightening to think that a person could go on writing the same book forever.