I have about 20 projects (books and articles) started or sketched out but not finished, which beggs the question, Why am I doing a second edition on anything?
The answer is that I looked at it and saw that it needed it. It's like an old car. Either it looks good but doesn't work well, needing a tune up, or it runs well but doesn't look good, needing a paint job.
In either case, it needed something, so it was either junk it or get it road ready, so I chose the latter.
How many unfinished projects do you have waiting in the wings while you work on "the one"?