It really depends on the vibe I get from the prossie, what kind of mood I'm in, how much energy I've got, what kind of mood she seems to be in, how much I get along with her, the amount of time I've book, and just how things go on the day.
The whole building rapport thing? Well, I think a good prossie just does that naturally, without any need for any extra effort from my side. I just tend to pick the prossies that advertise the services I want, go and meet them, pay them, fuck them and get the services I want, then I fuck off and do something else with my life.
If I decide to leave early without using up all the time I've paid for, well she should be happy about that, as she's quite literally been paid money for nothing. Last thing I would expect is lesser service on a return visit because I didn't stay and chat with her. Then again, those kinds of punts like that, it's unlikely I'd return. Would rather spend my money on girls whose company I just naturally enjoy, who give me what I want without a battle and leave me happy, rather than try to make one into something I enjoy.