once a day at least in the bathroom, and i usually have a bag of those handy-flossers in my car, and it ends up being something i do during my hour commute. my reasoning: i didn't floss unless i had to dislodge something for a long time...until i went to the dentist one year and he said i was going to have to start or say hi to gingivitis and itty bitty cavities between my teeth (increase tooth sensitivity and uh, nasty looking). healthy gums = happy mouth. and if you beat your gums up with floss on a regular basis, it keeps 'em healthy. weird shit.
i answered the poll 'once a day' though because i forgot to get a bag of those lil shits for my winter beater so to be honest, i'm lately just a once a day girl.