My friend, the late Dr. William Wright, was one of the pioneers of facial plastic surgery. He taught me a lot, but his most memorable aphorism was this: Perfect is the enemy of good.
In the context of facial surgery, he meant that continuing to alter nasal bone or cartilage in search of perfection might leave the patient with a ski-slope nose or a nasal tip tilted so high that the nostrils showed. Trying to achieve just a bit more tightening of the face at the end of a face-lift could give the patient skin off which you could bounce a quarter and eyes that might not fully close. Not to get too technical (and it's probably too late for that--sorry), he was saying that you have to know when you've done your very best, then quit.
Isn't this true in most phases of life? Looking for that perfect dress or suit? Seeking the perfect skillet for your kitchen? Trying to find the ideal vacation spot? There has to come a time when we say, "I'm not going to find anything that is perfect, but this is good...very good. I'll take it."
Authors have this problem when they are doing the final edits for their work. How do you know when to quit? Does that scene truly work? Is this dialogue too stilted? Should I throw out the whole first chapter? (By the way, that often works well. In too many draft manuscripts, the real action doesn't begin until chapter two).
So what's the answer? How does a writer know when to quit? My approach is to write and edit as I go along, reading the preceding chapter and editing it before starting the next. When the whole work is complete, I lay it aside for a few weeks and then do another complete edit. A third pass precedes my submission to my agent (who will almost always have her own suggestions, which I take). Then the editor will do yet another edit. By this time, we hope to have achieved something that's very good. Perfection? I'm not sure I've ever read a novel that's perfect. But, after all, perfect is the enemy of good.
Have you ever read a novel you consider perfect? Would you settle for one that's just very good?