A couple of times I went four, and once went five (the last hour was OTC).
If I'm seeing someone for the first time, I'll ask if I can get two hours with the option of going for three if things are going well. There's only been one time when I didn't ask to continue for three.
I hate to keep repeating this, but I'm divorced just two years now after being with the same woman for 45 years. I'm uncomfortable at first (although getting looser), so I like a little time to chat.
It also takes me a long time to come, which is part age, part ED meds. At the session I had last week with a new provider, she talked so much (I couldn't get her to stop) that we had less than an hour for sex. The two hour buzzer went off, and I still hadn't come. She didn't do three hours without food (yeah, that one), so I left without coming.
Another factor is that, for almost all of my meetings, I have to drive to another state, and I spend the entire weekend travelling for that one session. Being gone 30 to 36 hours for a two-hour session doesn't make much sense. It doesn't even make much sense for a three-hour session, but that's usually what my budget is with travel. (~$1500).
I like to just run my hands over her, play with her ass and boobs, feel her hands, kiss, cuddle and lot of other things non-sexual.
I've asked to go from three to four hours a couple of times when I was really enjoying myself.
If I was in a city with some really good providers, I could see doing just one or two hours. I've often thought about just sticking to my area, and doing one hour "blow-and-go" sessions. If you saw what's available in my area, though, you'd probably puke.