From the 37signals post Workaholics fixate on inconsequential details:
Good advice for anyone who wants to be more efficient: When you’re sweating for hours over a tiny detail, stop and ask yourself, “Is this really worth the amount of time I’m spending on it?” If not, declare “good enough” and move on.
The perfectionist in me initially cried out, “No! You can’t just skim over the details like that!” But he’s right. It’s not a call for mediocrity. It’s a reality check.
I’ve been thinking about this in regard to my playwriting, for example. Say I write a play. I could revise it ad infinitum, and ostensibly it should get better over time, yes. (Though too much tinkering can be a hazard.) But is it worth it to keep revising? Some revision, yes. But there’s a point at which it no longer becomes worth the time I’m putting into it, and then it’s best to move on and write something new. You learn not only from polishing your current bit of work, but also from starting the next one. And the next one. And the next one.