How do you know the story is done?

On Saturday night, I e-mailed Red Hood's Revenge to my editor.  This is the time when we do the Snoopy dance.  (Or we would if I hadn't immediately turned around and messed up my back.  Sigh.)

Overall, the book took just over a year from the day I started writing.  The manuscript came in at 91,000 words, but I suspect it will grow once I have the revision chat with my editor, not to mention feedback from my agent and a few others (including one Seanan McGuire, author of the forthcoming Rosemary a