When possible, we try to grandfather clients in. I try to give out discounts when I can, but the idea is that they should be a welcome surprise, not an expectation. It's nice to do something nice for regular clients. Recently, YBenL, who posted earlier in this thread, had a less than stellar experience with one of the ladies I assist who charge a significantly high rate. I begged him to offer a freebie on me, which would mean that I would be paying out of MY pocket for the entire date. I did that because I've known him for years and the cost of one date is nothing compared to years of friendship and support. (He refused, but that's on him.)
But on the other hand, if someone writes to me saying "I only ever pay 400 for a date" or something, I won't respond. We don't need your money, friend.
There's also the fact that I keep meticulous notes on clients. Some ladies love some clients and other ladies dislike the same clients. When there's a good match, I'll move heaven and earth--including offering discounts--to make it happen, because a happy provider is a successful provider.
More on rates: One of the ladies I assist, a UTR provider, meets 2 clients a week. But she is in extremely high demand. In that situation, raising the rate becomes a tool to help me reduce my workload as an assistant. Instead of having to say no to 18 of the 20 people who want to see her at 450, I only have to say no to 3 of the 5 people who are willing to see her at 700. The higher amount is just a happy coincidence--the lady in question told me to prioritize nice clients over more lucrative ones.
Our situation is pretty unique since the ladies I assist all either go to school or have day jobs. So nobody wants to meet more than one client a day, maybe 3-4 days a week. At that low volume, it's easy to command higher rates because the lower demand that comes with those high rates become desirable. Most providers have a goal in their heads, be it in amount of money or in terms of clients they enjoy spending time with. They choose whichever equation helps them reach that goal.
If you are extremely clean, don't have halitosis or body odor, are well-groomed and polite, you'll get preferential treatment, whether it's financial or otherwise. I've noticed that the reviewers that give the highest ratings are often the same clients who are cleanest and nicest.
None of this is universal though--I have clients who are adored by certain ladies and disliked by others, and I work for providers who are beloved by certain clients and never repeated with by others. Isn't love wonderful?