I think this is something you need to discuss with a provider that you're booking.. No reputable provider will kick you out after 45 minutes, unless you're being disrespectful. However, something like msog during a long booking in my opinion has to happen organically. It all depends on chemistry, comfort levels, etc. You also have to be ready to initiate it and to be communicative. It's one thing to ask for 2-3 shots in an hour, but we are not machines, there's a difference between a booking like this and a 3 hour booking where non stop sexual activity is expected.. Do you see what I mean? You just have to be realistic here, and tell the person what you want.
I disagree that ''the best providers will allow someone to cum as many times as you want''... Personally I feel hesitant to allow a specific ''number of shots'' because it depends on so many factors. I say 2 shots for a hour long booking just as a guideline, but if there's chemistry and time to recuperate, 3 might be ok. Someone was mentioning on a similar thread that if some guy jackhammers for an eternity and doesn't care about the SP's comfort level, even if it's one shot, it won't be pleasant compared to someone who cums easily and makes sure the SP is enjoying herself and able to relax. lol
A little over a year ago I had an issue with a client before who always wanted a certain number of shots, ABSOLUTELY, every time, ''to get his money's worth''. I accepted because msog is part of my service. After the 2nd round, it became a pain to endure it, because he was having a hard time finishing. He would just get really rough and trying so hard to cum and I felt like an object, it was physically painful. (there was one time when I was sore for days after seeing him, so I'm not being ''fragile'' here..) I had to fire him after 4 or 5 bookings, for that reason among others I won't mention here.
I understand ''wanting your money's worth'' but if you have a specific number in mind you are not only putting pressure on the SP, but also on yourself.. Unless of course you know yourself really well, like the gentleman who commented above, and know exactly how far you can go. But that's not the case for everyone.. and it's not going to be the same way with each individual.