In the comments section of the previous post, some wise readers (hiya Marijke and Carleen!) noted that yes, you absolutely should aim to send out the best version of your work but that some writers are unable to stop tinkering, paralyzed with the thought that they could always improve their writing, and thus they never submit or send anything out.
And they're absolutely right. So this raises the very good question of how you toe the line between being overly neurotic and exercising enough caution that you produce a polished manuscript. I'm not sure that I have a good answer because this is something that I've learned on the job by having the very good fortune of having a wonderful agent and wise editors, all of whom have taught me how to pinpoint weak spots and really crappy writing. But, if I'm going to make my experience more universal, maybe one good gauge is to have a writing partner whom you trust, and if he or she deems it worthy, then indeed, you have to trust him or her and send that baby out the door.
The thing is, is that there will always be ways and places to improve your work. If you think that I don't spot sentences in The Department that make me cringe, you'd be dead-wrong. Hell, there are entire passages that I can't believe I actually wrote, but I have to let that go. Because I could spend my life fine-tuning and there would still be new places to fine-tune...it's sort of like tweezing: tug out one stray eyebrow hair, and you'll find another just as quickly. So for me, as long as my figurative eyebrows are in place, I know that I have to step away and let others work their magic...which in my case, means turning it over to more objective readers who will help me tweak the areas that need to be tweaked.
But what about you guys? How do you know when you're good to go? And how do you step back and gain perspective?