I recently wrote a feature script in two weeks, did some editing and then had some writer friends offer notes and check for any typos and omitted words. I just watched a William Goldman interview this week and he wrote one of his features in three weeks, which didn't surprise me. He added that he would typically do three drafts. I've only done multiple drafts, usually three, for optioned scripts where producers requested changes or additions. However, I often revisit older scripts and do revisions before I send them out. My standard is higher now than it was a few years ago. But I never labor over the same script for months. I think it boils down to having a clear picture of where you're going before you begin typing.
What say you?
How many drafts do you typically write?
Is there a magic number that works for you?