Obsessively every day (usually about 50 hours a week) when playing it then take a break for a few months and then back to it on the same schedule. Of course, I'm obsessively playing something else if I'm not playing Skyrim.
I don't have a life.
Agree other than the battlefield/fifa stuff. I do other RPG non-shooter games (DA-I, DA-O, DA2, DD-DA, SoM, Bound by Flame, Oblivion, etc...).I go through phases.
I'll play it every night after work for about 5 hours, then most the day sunday for a month or so. Then I'll have a month or so off gaming completely or just play a bit of battlefield/fifa now and then. Then back on skyrim, back off.
Nothing better to do after work really. Sunday is usually hangover day, skyrim is perfect for that.