I used to like long gaming sessions but tend to play in hourly chunks these days. I can get drawn in and still be playing after that, but on the whole about an hour does it. I find I can remain focussed and absorb the game better, rather than just having it wash over me. Of course, the game itself might keep me locked in but I find that isn't the norm these days. Some of that will be me, but some is definitely the nature of the games I end up playing.
Once again I'm reminded of just how much I love this game. So much to do, so many choices. In the past I've researched the path to specific endings but this time I'm just going with it to see where I end up.