2-4 was my go to. 3 hours seemed to be the sweet spot for me. My sessions weren't really elaborate. But i liked to pace myself take breaks, not feel rushed, chat etc. a while back i also starting including social time in my session requests, normally dinner and that would stretch it out to about 6. I got the impression that wasn't a common request but it turned it into a nice date for the evening and a lot of fun.