I've been writing for 6 hours, with few breaks. Only, I haven't really been writing. I've been editing. And editing. And re-editing. Reshaping my thoughts, re-wording my phrases, and re-saying every little thing.
Honestly, I don't feel like I've done much. But comparing the first paper and the final product, they're barely the same thing. No surprise, the finished product is volumes better.
It pays off.