a lot of comments here dance around the "quality" of hours. the "flow" state you describe is quality time. we all pretty much like that. on the flip side, if

a lot of comments here dance around the "quality" of hours. the "flow" state you describe is quality time. we all pretty much like that. on the flip side, if i'm at home 12 hours a day but my wife is in the other room and my child is watching tv while i'm on my phone checking twitter and hacker news... you get the point. all these numbers and thresholds are practically irrelevant. quality of time spent is key...