of the type of customer you are. When you talk to providers outside the incall, you have to limit the conversation to only what is necessary to book an appointment. If you want to have a conversation with them about their own interests, history, or life, do it while you are paying. Otherwise, most will regard these communications as your attempt to "steal" OTC time from them.
Providers hate timewasters, and they have all experienced them, i.e., guys who want to chat them up, and then who end up never booking a session. If you become a regular, and once you have seen her three or four times, the rules on outside contact may relax some, but it depends on how busy she is.
From these kinds of experiences, you hopefully should learn where the "tipping point" is between acceptable pre-booking conversation and being judged a timewaster. Timewaster names have a way of spreading throughout the hooker community to the point that you may not be able to get a session with several girls in your area. If you are annoying enough, they will tell others to watch out for you. Then its going to be just you and a bottle of lotion on a Saturday night.
As a side note, many girls consider 20-questions before you have even met to be kind of creepy and stalker-ish. You don't want to be THAT guy, either.