I just want to enjoy myself and have fun. Thinking too hard is not fun. I do what feels right at the time. No set rule.

Don't over think things. It's sex.  it's supposed to be fun, not a guessing game. If it feels right fucking the same woman ten times in a row then do it. If you feel like trying out a different gal then do it!

These are decisions that are made with your libido not with a probability analysis...

After a couple of Newbie mistakes, I found TER.  I actually went most of a year with an excellant provider whom I because quite fond of.  There in is the problem, it is very easy to slip accross the line with a pleasant GFE provider whom you have great sex with.  This is the protect the women & off spring hormones...  useful with the dinos & cave men out there.  Kind of obsolete now.
I enjoy Favorite partners whom I rotate.  It is helpful to keep my perspective.  Still I occasionally meet a new prospect.  I am not interested in notching my six guns as many times as possible, so I do not meet ladies whom I do not feel are "Possible Favs".  Sometimes I am right, sometimes not.  
I still see that orig Favorite from time to time...  but it is not exclusive.
skb

1) Once

2) Never had an ATF

Regarding #2, I would not brag about it, since others will wonder how come they are not your ATF. Think not? Try it you'll be sorry.

If I could find someone in my geographic area who was a 9, I would look no where else and see her as often as possible. But I live in a vast wasteland as far as providers are concerned and need to travel 2 hour to meet with the 9's. So based on scheduling issues, when I am traveling to the big city and geography, I have seen a variety of wonderful ladies within a 2 hours drive, but I would prefer to stay close to home and find a regular in my home town.

And then off I go.  I actually tend to stay with one provider for a long time.  I like building the emotional bond and learning likes and dislkies.

I haven't found a need for variety. I do need that visits remain mutually respectful and on some basis of equality. Given that I can repeat on the order of 20+ times.

On one occasion those terms were not met and I became unwelcome after not being willing to assume a junior partner role.

Since then I've stopped using the term ATF.

Paradoxically my current friends are better for me. We are able to communicate and plan on a clear and reasonable basis.

Likely their need for variety and relief from my dubious companionship will drive the dynamics, not mine. I lke the familiar and comfortable, healthy and functional. I'd always rather spend energy and money on what I know is good for me rather than risk an unknown.

That question is as convoluted as the answer I'm going to give you

In my limited experience, I do indeed have ATFs for different reasons.

My ATfs are ATFS because they each provide a different experience.

I met a lady just last week that could easily become an ATF, with another session or 2.

She contacted an ATF to screen me, which of course I went thru with flying colors.

These ladies are special to me, and I know I'm special to their business.

That being said, there are some that I will repeat with again and again.

I repeat 2-3 times then move on

Some guys want the newest, hottest babe out there and will never want/find an ATF.  Others want variety and thing any repeat date is too much familiarity.  Some want more of the GFE evolution.

I wasn't looking for one but it took 2 visits for me to know who my ATF was and the second one only to confirm it.  For 10 years I've probabaly seen her 20 times a year or more.  Not tired of her in the least and doubt I ever will be.

A couple others I doubt I would ever have gotten tired of but they went off the market.

True ATFs are not a number of visits.  It's an "I'll know it when I see it" thing.

about 3 years running.  In both cases I saw others as well but always came back to them for a "sure thing".  So I guess I had my cake and ate it too.