I have found 100 other reasons why a session is perfect for me and time was never one of them. Set your watch for a 45 minute alarm and you focus on leaving 15 minutes early for your perfect session. If you pay the hour fee and leave early regularly, you will be appreciated by the house and the provider. If you are haggling over 10 dollars, you will be flagged as haggler and cheap customer.
Don't focus on the time and money, focus on the quality of service while you are in the session. I have had session that started as soon as I walk into the room and at 45 minutes I am crawling out the door panting and smiling at the same time. The woman could have my entire wallet and I would not give a shit.
Please try and make that your goal.
Go to the Philly Reviews and read Jim H's review of Angela for a perfect example of your session nirvana.