I'm really glad that I did NaNoWriMo last year; without that experience, I don't think I would be able to do this effectively. I have an over-developed inner critic which makes me obsess about finding just the right word. Learning how to shut that critic down ("I'll edit later! I swear!") means that I can write thousands of words a day if I have to. It's not just useful for writing contracted work, it's an immensely useful academic skill too. And as long as I keep my editing promises to myself, the writing turns out just fine!
I'm going to see if I can get another 200-500 words done, then head outside. God, I love May in Central Park . . . .