i usually spend my time 14 hours a day cause i do have many sites that are managing that's why i stand pretty long hours here and i also love making some web designs. :Scary-Smile:
When I was doing my thesis, I usually spend 12 hours minimum on my laptop. I went to straight 48 hours with it sometime the day before our defense for the programs that we were making. It's nasty.
The longest time was 8 hours I think. It's not that much I know, coz I have a lot of things to do in a day but being infront of my PC is the most time that I spend.