The most I have done (in a row) has been 7 CYO games, approximately one hour each. I have decided my limit (physically and mentally) is between 4-6 depending on my physical condition and the amount of focus I can muster.

I have a friend who did 14 games in a row. 8am-11pm. Highly inadvisable, as for the last 5 games he hung out as Trail 20 feet into the backcourt.