i agree with marsupial mama. i write on a lap top with the kids playing aroudn me -- sometimes it works, sometimes they want to play with the computer
i write flash fiction. under 1K, and mostly under 500. when i wrote a 2200 word story i thought WOW this one was LONG
some of my flashes are very very short, or sort of prosepoems.
i find satisfaction in this -- i can write a draft without loosing the track, and then i can edit it slowly, over several days, almost sentence by sentence, at different times of the day, without being burnt out.
now as i have a 4 y o and a 20 m old, i can't belive how much time i wasted when i had only one!
when dh comes home late, i manage (touch wood) to have both asleep by 9PM, and then i can write a bit, if i am not too exhausted by then
when dh is home, he stays up longer with dd, and then i can write a bit too.
i think the worst is when i PLAN on writing, and then something happens and i don't find the time. then i sometimes get impatient and cranky. so i try not to plan on anything