I'm on mine from 8-5 M-F (minus an hour or two per day for lunch/meetings). And it's plugged into an external monitor, keyboard and mouse, so the only onboard keyboard/trackpad/screen remain off.
I leave it in the briefcase at night so I can give attention to the girlfriend/friends.
On the weekends I'd say I'm on it a total of 1-3 hours, if at all.