Personally speaking, apart from parties, I have never booked a girl for more than an hour which suits me fine. Ultimately I see prossies for sex and nothing more. Yes, I like a bit of GFE if that's part of the package but GFEs and longer bookings are not my main criteria for booking a girl. I suppose the GFE and dating side of things are taken care by my FB whom I meet occasionally. When we meet we go out, have a meal, have sex, etc. Also being married the emotional attachment to a woman is catered for. So that just leaves sex for the sake of sex... for that I book prossies either for half an hour or an hour tops.
Like Smiths observed I have also noticed some punters having just one pop at parties and that was that. At first I was surprised especially since some of those punters were young (or younger than me anyhow) but then I realised just like everything in life whilst we all have some commons tastes and likes on the whole we are all different and whatever suits one will not suit everyone else.
Lastly there is one more factor to consider, again personally speaking, some prossies are just so damn good at making you feel amazing that if I booked them for longer and saw them regularly I would fall prey of the Emotional Attachment Syndrome and get all infatuated with them. So short quick bursts of sexy prossies keeps me safe in that respect.