A book is never, ever finished. You simply get to a point where you and your editor are reasonably happy with how it is and you go with that. Left to our own devices, a writer would endlessly fiddle with a book, changing little thing after little thing. ↗
Men could not part us with their worldly jars,
Nor the seas change us, nor the tempests bend;
Our hands would touch for all the mountain-bars,--
And, heaven being rolled between us at the end,
We should but vow the faster for the stars. ↗