I've had the same concerns, but I believe that if her contact info (email and/or #) is allowing you to reach out to her ... you should be okay! BTW, very good question because it's one I was meaning to ask, too.

The most likely is she was retired for a year.  This economy is bringing a lot of providers back into the business.  Another very common reason is she retired to be with a SO and that relationship is now off.  Having a child will do it as well, especially if she was seriously working to regain her pre-pregnancy shape.

If you are concerned, ask her.  If done politely I don't expect most women would object.  It also shows that you have been doing your research and that is a positive with most the good providers.

and then little or none in subsequent years as she is busy seeing her regulars who already reviewed her.

Not a problem in my opinion.

A year is a long time and a lot of things can happen then. If this were my first encounter I'd want someone I had more recent dope on. This would be a lot less risky than TOFTT with a totally unreviewed provider but wouldn't you want your first time to be as close as possible to what you fantasized it would be?

I don't know what the selection is in your neck of the woods but at least in mine there's more than enough to not get hung up on one lady. Six months unreviewed is probably the longest I keep someone on my list.

I didn't retire, I wasn't in any hot water, I haven't been sick, I did not have a baby.  Most of my friends are regulars, I live in an area where TER is not the popular board, and I simply don't ask for new reviews.

If you are concerned you might try asking on your local board for current info on the lady, and/or try pm'ing some of the past reviewers to see if they know anything about her that is more recent.

A stretch of reviews may be something to question, yet it's also very common for a number of reasons.
: )

My favorite lady has only a couple of reviews that are less than a year old. There are lots of good reasons for lack of recent reviews. Already mentioned is that well-established, highly regarded ladies may see mostly well-established regulars. Also, this may not be the primary board for her. Also, she may be sufficiently established to the point that she does not request, or possibly does not even want, lots of new reviews posted here. PM a couple of recent reviewers of the lady you are considering to find out her current status.