So far I've finished a half-done story; written a story from scratch; typed up a ridiculous number of words in D&D campaign journaling (like the old CSI: Luvine stories, but I haven't found the magic spark to make the stories truly cool yet); and am most of the way through writing up a really vivid dream I had in October. Plus I counted about 500 words that I'm about to edit and reprint below -- it was originally written as an LJ comment in a friend's journal, but it was important. (I'm not counting the few paragraphs of blather here, though. I have my limits.)
> [I] can't really just write regularly like that. ... NaNoWriMo makes [writing] very regular and machinish. ... [I'm] hardly that sort of machine.
If this sounds like something you would say in criticism of NaNoWriMo ... then, first of all, let me make this clear. None of what I say should be taken as criticism of what works for you.
That having been said:
I am the worst sort of burst writer. My inspiration is erratic, I block easily on long-term projects and get distracted easily when I'm blocked, and sometimes I find myself going months without getting anything of value written at all.
I'm also a three-time NaNo finisher.
While the material I produce during NaNo is generally decent enough for me to appreciate having written it, that's not its real benefit. What I truly appreciate about NaNo is its ability to knock me out of the expectations of my own head. I start with nothing but a word-count goal and some minimum quality standards, commit myself to set aside the majority of my social life during the month, and treat the whole thing as an experiment in boundary-pushing.
My first real NaNo was done solely to discover that I can finish, actually get to the end, of a novel-length work. (It also checked off a ticky-box on my ten-year goals list. There's a separate ticky-box for "finish a novel NOT written during NaNoWriMo". I haven't done that yet.)
My second real NaNo (four years later, I should add -- I can't do these things without a cooldown period) was done to prove it wasn't a fluke -- but also as an experiment in serial fiction, because I'd never done a long-form continuing story before. It's not continuing now, but again, I discovered I can, and that was vastly illuminating, and will help me the next time I develop a serializable idea.
I am still an erratic writer. I do not generally push inspiration when it's not there, and I still write best in sprints rather than marathons. However, now I know what it feels like to do both; I know how to recognize the traps I fall into when the sprint doesn't push me to the end; and I've written some pieces during multiple sit-downs that I never could have done at a sprint.
One of the pieces I'm most proud of writing is a product of that. It's a product, in fact, of my "failed" 2006 NaNoWriMo, in that I set aside to write 50K in interweaving short stories and then finished November at a fraction of that.
Do I feel disappointed about failing? That assumes it was a failure! I blew a word count goal and produced one of my life's best pieces of writing. Should I have been disappointed? That depends on what my goal was. And there's nobody measuring that but me. The lesson I took from 2006 is that NaNo is, at heart, a learning experience -- a Rorschach test, if you will, of looking into words and seeing yourself.
And what of the years when I did reach 50K? They've been a slog. Sometimes, yes, writing means trudging on without the muse. But that's part of the learning experience, and when you're done, you've had the experience of doing it, and then you stop. NaNo's goal is not to train you to write without your muse -- just to convince you that you can. And to teach you that sometimes doing so can get you more of what you want -- more words, more satisfaction -- than waiting for inspiration.
I think I again need to emphasize that the NaNo I'm most proud of is the one where I failed, because I got an idea dumped into my head that really was worth writing about, and I stopped and did it right instead of forcing myself to live up to those external expectations.
That's the crux of it, right there. While my writing style is spectacularly unsuited to a one-month novel, the reason NaNo has repeatedly worked for me is that I have made it into something that I want to do, and once that happened, by definition it was a success no matter how far I got or whether I met the initial arbitrary goal. (I mostly have, but, well, whatev.) I didn't even try NaNo'ing a novel until four NNWMs in; my first two were an "I'm going to write a journal entry a day!" variant and my third was "One short story per day" (which actually ended up being even more of a muse death-march despite clocking in at ~40,000 words. After that, focusing all my effort on a single novel seemed like a welcome change of pace).
And if you have a muse, and some writing talent, and a deep-seated hatred of NaNo, and a little envy of the people who can write 50,000 words in a month? I need to mention how awesome it is that you can work without that NaNo crutch. The vast majority of my writing progress has been with it, in one form or another. And every time you start feeling like you need to be jealous of me for being able to finish a NaNo, take a look at my journal and the five-week dead silence leading up to 11/1, because I guarantee you that the envy flowed the other way while I was stuck. :)