They never are. Honestly. I used to scoff at stories from the Fall 2008'ers about how they wrote 20-30 drafts of their goals essay. And then I ended up with 17 drafts myself before I decided to call it a day. 17 is the magic number these days it seems.
At some point the law of diminishing returns takes hold and the amount of time you expend on making your essays just a little better is better spent on a different school's application. Especially if you're doing 6 applications for R1.
Give yourself a deadline, and once that deadline is here, wrap up your essays and move on.