Another day, another final, final re-write!

Have I at last finished my re-write of The Widow's Revenge?  So why do I keep finding sentences I can improve?  One minute I am truly happy with what I have produced.  Then I do another, last, read through and think, oh no, that word needs to come out.  I'm satisfied that I have weeded out 10,000 words from the version on Amazon at the moment.  That despite the fact that I have improved and extended the final few chapters.  A tough learning curve.  Will it be any easier writing the sequel?  I somehow doubt it.  Do other writers suffer these agonies?  Trying to polish every sentence?  When to let go of your baby and send it off to make its own way in the world?  I think I am close.....