Is it encouraged to review the same provider more than once or discouraged?  Or does it depend?  I've generally reviewed only once unless something significant changed (for better or worse)...

You can review a provider more than once but you will not get VIP credit days for subsequent reviews.  Also, your first review will come down though you will still see it in your account manager list of reviews.  I've done it a couple of times with girls that I kept seeing for a year or more.  I'm not sure what TER considers an adequate elapse of time between reviews.  In my case it was over a year each time.

I reviewed a provider a second time after more than ten years had passed. When I posted the new one, the original review disappeared. I don't know if it was a glitch, or if it was the result of TER policy.

I only review 1st dates now..

they never allow the second date.

Most but occasionally, I get a 2nd date with the same lady. Must be slow.