It's easy to under-edit and send out work that isn't ready. A beginner's mistake. We're anxious, excited to let our creations loose.
Once we gain a handle on our impulses, however, over-editing becomes a problem. We sit on things too long, trying for a perfection no work has ever achieved. We listen to every bit of feedback and incorporate it, no matter how contradictory. We lose our way, and the writing isn't the same... it's worse.
We writers work our butts off to make our stories and poems seem seamless. We often complain about how many drafts we've gone through or edits we've done. But, below that whine of the overworked, is the boast of the immensely dedicated. We want other people to know how hard we try. Heck, some even want to foster a pure and constant jealousy among fellow writers. I'm on draft twelve, but it's nice you're on four, so... quaint.
I partly blame universities with MFA programs for the over-edits. Editing is an extremely important skill to a writer... one that can be taught. Programs emphasise editing, sometimes to the detriment of other valuable skills because it's easier to teach. They make students use the amount of revision as a measure of how things are progressing, how they're progressing. If pages redone is the major measuring stick instructors hand students, how do you think they will continue to measure success during the "in-progress" phase after the degree?
So, I encourage you to break the habit. Edit vigorously, yes. More than once, certainly. But, when beta readers/your agent/Mr. Snuffles (your cream-colored rabbit with the one floppy ear) are telling you to submit... do it! Don't seek impossible perfection, don't think five more rounds of revision is more impressive... just go.
And then tell me about it. I'll cheer with you.
Do you over-edit? How do you know when it's enough?