When I first started in the hobby about 20 years ago, the appointment ended as soon as you blew a load.

These days, many providers offer "multiple shots on the goal" (MSOG), which means as many pops as you can reasonably manage within the hour. Realistically, they will help you go for a second load within that hour, but not necessarily a third go. Depends on how much work it will be for her.

If you have VIP, this is actually a searchable item in the TER database.

it depends on the provider.  Some will allow you as many as you can manage in your time with her.  Some will say, you are one and done.  There is no hard and fast rule for the number of pops a guy can have.  If you do your research on your providers, you should know ahead of time what you can expect.  Read her reviews, that should give you a good idea of what you can get.

LLAP,
Swim

a quality provider will give you the full hour of her time and fill it up with massaging, cuddling, or at least some chat.

and you will get an idea of how your session might go.

GFE providers will generally (but not always) allow MSOG in an hour encounter.

Cheap BP girls will generally only stay for one pop. Same with massage girls, but they are often good about pacing things to last longer.