I try to make sure I write every day. At a minimum, I try to make sure I crank out 1000 words every day during the week (I have a day job, after all), and on a day off (during the week) I feel that 3000 words is a responsible goal.
There are limitations to this, of course. I don't often hold myself to the 3000 word goal on my weekends unless I've got nothing at all going on. Sometimes my work day sucks and I know my mind is blown and I haven't the energy to write. I live with my girlfriend and our cat, and both housemates need varying amounts of attention, time and energy from day to day. They deserve as much as I have to give, of course, so when one of them is in need, the writing comes secondary.
I've got a relatively busy social life, too. I'm an adult gamer geek, as are the vast majority of our friends. I should note: nobody lives in their mom's basement, nobody has comically low social skills, they've pretty much all got real jobs (or understandable short-term unemployment; turns out the economy still kinda sucks). The gamer stereotypes so cherished by ignorant television executives simply don't really apply anymore. Anyway, all that means I have plenty to do besides write.
But I need to write. I want to write. The stories, they kinda have to get out.
I have found that my measurable productivity has slowed over time. I'm pretty sure that's because I'm more thoughtful about my work. I want to make sure I'm happy to put my name to something now that I have a few successes under my belt.
So, yeah, a thousand words a day/evening is a good goal.
But I gotta say, for all you Good Intentions fans: the moment Rachel steps into a scene, the word count just kinda explodes. And it's not even all expletives.