The only time I find it too long is when I am not into it or it is a bad session. Then it really is just nut and leave, or even just stop and leave. Those are the sessions I wish I never started, much less wanted to quickly finish.
When I'm enjoying it, I find sessions generally too short. If I like her company, and not just how well we fuck, I'd spend more time with her if I could, just chatting, cuddling, and so on in a more naturalistic sort of way.
My brain can understand the paying for fuck-time part, but if the rest was not on the clock, I'd let it go on and on (unless I had somewhere else I needed to go afterwards, etc).