There are no rules or guidelines, every guy is different, some are on a constant search for something new and some like the familiar. For me it’s a bit of both.
Go with whatever feels good to you. If you see an escort and have a great time, see her again. In my experience subsequent dates tend to get even better if you seem to have a good rapport together.
If you see an ad for someone else that sparks something in you, go for it. (after doing your due diligence of course)
Above all, have a great time!!