I'm not an 'older guy' but thought I'd chime in anyway. The majority of my sessions are 1-shot. It's tough for me to get 2 in an hour so if that's something I want to do I'll book a 90-min or 2-hour session - and even then sometimes it's only 1.
I prefer to take my time, even on the longer sessions, and make sure there's plenty of time for all activities.