I like your idea Julia. For me it would make screening a lot easier if there was doubt about me.
Obviously this will vary depending on the clientele and where the lady is advertising, but I wonder for ladies who put effort into getting TER clients, how many of those clients leave a review? Just always been curious.
And for you guys... do you always review? Only when it's been really good or bad?
Me... I usually review but if something happens that seems just too far out there to be useful to the board I'll pass. So for example, I once saw a super highly ranked provider (maybe 9.5/9.5), we got into the session and it turned out she had forgotten condoms, and we both believed in no glove, no love. She did offer me a partial refund and was nice and appropriately embarrassed about it. I thought about reviewing and giving her say a 6 for performance, which technically she deserved, but just couldn't bring myself to do that to her hard won average so didn't review at all. FWIW
I'm 4 for 4. Due to my limited experience I generally grade according to previous grades. Verbally I try to be accurate in my descriptions. Of course I can't remember every step, but as close as I can.
I think a review is a nice gesture. So far I had four good encounters. I suppose if I had a poor encounter I would perhaps not review. If I had a terrible encounter it would probably depend on whether it was malicious or not. Then I might review in the negative. Although that can backfire. It might be wiser to let it pass unless it involves someone's safety.
I didn't think to ask my first provider if she wanted a review, and not my fourth because she didn't speak English well enough for a convo. But otherwise I will ask now before writing a review.
I doubt they will typically say no. I depend on reviews, so I view them as good for the provider. Why wouldn't she want more?
it's your right as a paying customer and member of this site. Some would say it's your obligation to help this community of mongers be informed, but I won't go that far. There is never ANY reason to ask a girl if it's OK for you to write a review. It's not her call. Remember the "R" in "TER." It stands for Review.
Of course a courtesy is never obligated. But that's why they call it a courtesy. And that's why they call me a gentleman (to my face, ha ha.)
That may not be a worthy reason to you, and likely many others as well, but that is his reason. Who are any of us to say it is not valid? We each have our own standards to which we adhere. 
Another "reason" might be if one wishes to see a particular provider again. If she didn't want a review for whatever reason, she might not agree to see that writer in the future. Probably not common, but I'm sure it happens.
xoxoxooxoxoxoxoxoxoxoxoxoxoxoxoxooxoxoxoxoxo
"Who are any of us to say it is not valid?" Gosh, I had no idea I had no right to an opinion.
Your last point is just lame. "if one wishes to see a particular provider again?" Really? If I had a good time and wanted to see her again I'd write a positive review. If I wrote a negative review, why would I want to see her again? You are just goofy, Debby.
Absolutes just don't work well in this big world.
Examples from my experience as to why it's a good idea to ask the lady if you can write a review:
* Provider is UTR in general.
* Provider delisted because of a "revenge" review that wasn't removed at her request and depicted stuff she'd never do. If a new review were posted, her old profile and reviews would return.
* Provider is usually ok with reviews but is super busy at this time (e.g. heading into finals in school) so she'd like to keep a low profile now.
Of course, if there was deceit or some other bad situation that other mongers need to be warned about, the review should be written if the monger wants to do it.
I only review once, even if I have seen them multiple times.
I hope it helps them do well.
If I have a bad experience, IE
The lady that thought I didn't leave an envelope full of money
The lady that wanted to change my date time by 15 minutes 90 minutes before our date
The lady that was so wasted she fell asleep blowing me
The lady that needed a little extra for her child for Christmas
Then I don't.
It was probably my fault
If every client of a gal always wrote a review, TER would need 10 times more servers, most likely.
I do review unless a gal has asked me not to. That's only been about twice.
It pays to bring condoms with you in a sealed box
...so why don't you tell us?
Close to 33% write reviews, possibly higher around 40%. Alluding to what Julia said, I actually prefer women who read clients reviews, on the flip side, we read theirs and any respectable man will adhere to what a provider likes and dislikes. I would say I don't have a system down as far as when I will write one, but rule number one for me is if the session was super hot then I will get the review out super quick so that I don't forget all the details. I have waited as long as a couple of months to write a review on a provider and I have written one as quick as one hour after.
Where did you get your numbers?? 33%? 40%? That's way high. This topic has come up over and over since TER began. Of course there are a lot of variables, regional and otherwise. If a lady only advertises on TER she probably gets more reviews (percentage wise) than a provider who advertised elswhere.
Anyway the number that has always popped up time and again is about 1 in 10 write reviews, so the statistic I pulled out of my ass in the post right above is a lot more accurate than the statistics you pulled out of your ass. 
...and I always review a great time unless the lady asks me not to. I don't review a YMMV situation (where I have a significantly less positive experience than her previous reviews would have indicated), unless there is notable negligence on her part.
between 5% and 10% overall. (that's 1 out of 10 to 1 out of 20 for those who are math challenged). I assume that's all clients, not just those with TER accounts.
I review approximately 25% of the providers I see. More likely to review a massage girl than an escort in general, partly because there are so many body rub ads on BP and elsewhere and so few of these girls get reviews that I like to think my review is beneficial to this community.
Likewise, I'm also more likely to review an escort if she's relatively new and/or is seeking reviews. I have never been asked to NOT review.
I'm far less likely to review a girl who has 30+ reviews. Really what more can I say that hasn't been said, and I don't need the extra VIP days.
To the OP who didn't review a highly rated provider who forgot the condom, I agree with your "no-review" on an incomplete effort. If she hadn't offered the partial refund I might feel differently
That number has been around a long time. Tried and true.
I review every first time visit unless the girl says she does not want to be reviews. Then again, I see very few who don't want to be reviewed.
I don't write reviews for repeat visits, except for one girl who had been in a slump in her reviews
Not to mention a BP provider might see a hundred clients before ever getting her first review. A lady who does a lot of advertising here on TER might get one out of every three or four clients to review her, and a lot of women, especially the HDH variety try to avoid the typical TER reviewer and most likely only get one review out of every 20+ sessions by design.
Like I said, "one in ten" is nothing more than a stab in the dark, the real number is a varied as the hookers getting the reviews.
at the current time.
The only exception is if the service is below standard compared to her reviews. Then it is only fair that I let fellow mongers know there is a negative change in her performance.
If a provider gets reviewed one out of every 10 times there's no way they can make a living. I've done the math on some of the higher volume/active ladies I know and at 3 to 4 appointments a day five days a week for a couple years there's no way they should have 50 to 60 reviews. Just saying.
If they're only adds are off TER then maybe one and 10 is accurate, I don't know. I've reviewed roughly half. Theres some I do not want to review because I don't want anyone else to know how awesome they are, I'll pretend I'm her only client. Another one I won't review as she was unattractive enough that I felt bad afterwords and don't want to have to look at her picture or claim it, the body was good though. LOL
maybe i'm spoiled by my wonderful atf's who make the 8th session as wonderful as the 1st, but i have recently seen 3 different ladies who gave a fantastic first date, and then a couple weeks later, gave me a second date with little to no enthusiasm or focus.
if there seems to be a need:
1. New providers with no or few (less than 5) reviews... reviews every time.
2. A provider with no recent (reviews more than 4-6 mos old) reviews... consider reviewing.
3. If something is vastly different from other reviews... consider reviewing.
4. For a fantastic or really poor session... consider reviewing.
5. If she asks or I just feel I should (usually a fantastic session)... I review.
6. If she has a no review policy... I respect it.
Overall, maybe a review 5% of dates.
I always ask if they would like a review, some do some don't. Also, I see many ladies who are not members, don't have websites, and are just drive bys.
And for you guys... do you always review? Only when it's been really good or bad?
Me... I usually review but if something happens that seems just too far out there to be useful to the board I'll pass. So for example, I once saw a super highly ranked provider (maybe 9.5/9.5), we got into the session and it turned out she had forgotten condoms, and we both believed in no glove, no love. She did offer me a partial refund and was nice and appropriately embarrassed about it. I thought about reviewing and giving her say a 6 for performance, which technically she deserved, but just couldn't bring myself to do that to her hard won average so didn't review at all. FWIW.
I am starting to do reviews now on a more frequent basis. I have been as I am sure most of us have - duped before by a dishonest provider. To help ensure that hobbyists have fun I will write a review on any and all providers I see as I have learned my lesson. My advice tell us people what we need to know about a provider. Thank you.