I realize reviews, but does it matter if the provider pays to advertise anywhere else besides TER?

Legit as in looks, appearance, up to date pics?  I look around on other sites to see if she has ads up Eros, Tryst, P411.  That's mainly for consistency e.g. same phone number, email, contact info etc.  Some providers link their work IG to an acct, which is good enough for me as far as paid advertising goes.  If I had to rank sites for verification I guess it's 1) TER 2) P411 3) Eros (mostly for pics, contact info and current rates, city touring) and another review site in the southern region which I don't think I'm allowed to mention on here.  Legit as in service, TER and the previously alluded to southern review site are tops for me.  

My only criteria is if I can verify her or not. By "verify" I mean I can reasonably rule out LE, that she is who she says she is (i.e. her pics are accurate) and if we are compatible sexually.

1.  TER - For reviews, activities offered and price range (TER is often outdated).  2.  P411, personal website or Tryst (in that order) - To confirm legitimacy, verify pricing and schedule.

Eros no longer allows you to post your website. I receive lots of spam email from hackers on Eros & Tryst. This is the first time I have paid to advertise in years. Back in the day I had a personal CSR on Eros. It was very difficult to get on Eros & Tryst. I am verified, but when I look at analytics from my website the majority of my traffic comes from TER  & Twitter. I don’t think Eros is worth the money to advertise especially with not being able to link your website. Thanks for sharing. I appreciate the feedback.

Some are worth the money and some aren't.  

Review sites, back channel, and word from other providers, not necessarily in that order are what I rely on.

That is all that I require (personal site to verify rates and review photos).

I rely almost exclusively on TER for verification! I look for ten or more reviews, and I like to see 50-75% from reviewers with more than one review so I know the reviews are legitimate. I also hope to see a few reviews from hobbyists whose reviews I trust. We are blessed to have 50-100 providers in my price range ($300-600) in LA that fit this description at any time, and I probably have a list of at least 20 providers that I have seen and are sure to provide a safe and enjoyable session!  I was a member of another review and verification site for about two years, but most of the girls were above my price range, and several times I stretched on price and ended disappointed with the provider’s looks, service or both!  I cancelled after two years.  I do browse several advertising sites, but I still search TER for reviews before booking. I also take trusted booker recommendations knowing the experience will be safe even if the session falls short due to provider looks or service.

Don't have P411 and probably will never sign up for their service, right now.  
My verification in order of priority:
1. TER (ok, i should get at least 1 month of VIP days. 2 weeks???😁).  
2. Look for reviews from reliable reviewers. Read the general discussion boards, reviews....
3. My own verification factor. Ladies with first  and last name and not only one name, with the exception of Thai ladies and few others I've met. That's what the ladies ask for, right! 😉