Where can you see how many hours you've played?
/

If playing on the PC it shows on Steam when you Shift+Tab during the game (same spot as achievements).

I just know that I have been playing way to much. 34 hours so far on Steam and plenty to go. Just the start of a marathon.

If you look at your loads or saves it says how much time

lol im on 44 hours atm

20 hours, would be more but my brother came home for the weekend to play it. I've actually not done many actual quests at all, I've just been wandering... this game is great for doing that.