I always write the end first. Even if I don’t have a clear idea about what my hero’s journey will be, I write the end first. It is my innate need to know where I’m going. The only way I know when I’m getting to my destination.
Also, looking back has its advantages. You can see clearly what shouldn’t be in the book as well as find new subplots by simply asking “what if?”
It might be perceived as a limitation, but for me is the best way I found to convert all my effort into writing a complete, compelling story.
If I don’t feel the need to change the ending while I’m writing the book, it means that is a good ending, one I believe in.
While the beginning of the book determines a person to read your story, the end will create the need to tell others about this book and buy the next one.