Here's a far-too-vivid description of a novelist's drafting process, from an interview with China Miéville:
CM: Yes, I'm finishing a novel right now. I've finished the first draft. An analogy occurred to me, as I stared at this beautiful, fucking messy thing. When a cat gives birth to a kitten, it then licks all the manky crap off it for an hour. So the transition from first to second draft: I have to spend a month licking afterbirth off a kitten.For a precious few of us, our sketches and manuscripts will eventually be sought after by collectors or archives (for new music, the most prestigious archive has been this one). For the rest of us, it's all about the practical issues of living with the mess and figuring out what to do with it when we're done. By moving to composition directly into the computer, I will cheerfully admit to making it difficult for future musicologists to trace my steps and less cheerfully admit that I am separating myself from at least a tiny chance of someday generating income from the sale of manuscripts. I have kept my manuscript juvenalia, but even with that, there have been moments in which I have almost convinced myself to reduce all my files to finished and digitized scores and to barbecue the remaining paperwork, but the moment has never lasted long enough to turn into concrete action. So I still have a small stack of paper manuscripts as an emblem of my antiquity and will otherwise continue to work without leaving any of that manky stuff behind.
JP: That's a great analogy.
CM: I thought so. Thank you. It's hideously accurate-feeling.