It depends a bit. I've had up to 100 - 120 games too, mostly 1 turn / day, but on 'busy' days, that was way too much. Not because I had to make a move in every single game because of time constraints, but because I had no rest in my head if there were too many games I still had to play at.
Then again, now I'm 60 - 70, but quite some of those are with people I got to know better and play with on a regular base. Sometimes those are going too slow, so I find myself without turn based games to make a move in too fast to my taste. In the evening I don't mind too much, as I can switch to real time easily. During the day that is harder, so at those times I wish I had more turn based games going.
It also depends on the kind of games you play of course. To put it extreme: if it's 100 games of Solo, Yahtzee, Take 5, Can't stop, ... it's easy because it goes very fast and doesn't require much thinking. If it's 100 games of Dungeon Twister, Terra Mystica, Abyss, ... it would be way too much.
