Since I have been involved with this Hobby , in the back of my mind, I have always been concerned about picking up an STD.  The ladies I see are very clean, but its still a concern.  Does anyone have any additional thoughts?

five decades and easily 300 women.  STDs from same:  0

On the other hand, Among the ten or so civie I dallied with before marriage, I ended up with 3 STDs.

Do the math.

...and have had no STIs. Granted, I've been off & on in my participation, but there have been many women with whom I've had great playtime. I believe that's due to a provider's awareness of the hazards and that they are more reliable in taking steps to prevent said hazards.

I haven't had any issues with my civvie relationships, either -- but I have been involved with women who were less than stringent in paying attention to those issues. Not surprisingly, once I became aware of their inattention and lack of desire to change their behavior, it was an incentive to end my involvement with them.

Keep tested.Paid sessions without drama

Of themselves than civvie girls. Js.

The frequency really depends on your comfort level and your safety practice, who you see and what you do. Unless you engage in very risky practice, it's actually pretty safe. I am more paranoia so I get tested every 3-6 months. I know it's probably not necessary, but I feel safer. It's not cheap, but it helps me sleep better at night.

I've been in this game for 12 years, and 3 cities and 2 countries, and so far I've had 2 condoms break on me, plus one surprise bbbj that left me worried because I took for granted that all providers applied the cover, but that was when I learned that they don't. And despite all that I can honestly say that I never caught an STD. I guess I was just lucky those few odd times when the service was uncovered, but by and large I always apply the cover, and that's what I attribute my survival to. But I get that some people just don't like the feel of latex. Since that surprise bbbj episode, I have developed a more liberal view on uncovered service, and I'm willing to try it again someday, but only after the following safety protocols have been satisfied;

1. We both do same day STD and HIV testing for both our peace of mind (it has to be same day, and I have to drive her there myself and not let her out of my sight because it's the only way of making sure she doesn't sleep with another man before I get my turn)

2. I need to see documented evidence that she either tied her womb, or is on the contraceptive jab. (the jab is more reliable than the pill because then she doesn't have to worry about the possibility of missing a day, she just takes it once every 3 weeks and keeps it off her mind till next time)

3. I take her back to my place, and make sure that she takes a shower (external hygiene is just as important as internal hygiene)

And once she has been processed in, I can now enjoy her body with wild, reckless abandon.

Now these safety protocols for uncovered service is just a hypothetical concept unless off course you become her regular client, and you develop a kind of rapport with her that transcends bedroom activities, this is where YMMV comes into play. Also, those uncovered services are probably going to end up being more expensive in addition to you probably having to pay her for the time you spent taking her to get tested, and that's a lot of hassle right there. So if you want to go the uncovered route, you'll probably only end up doing so once in a blue. Otherwise, just use a condom and you'll be fine.

You make a good point that your approach is just hypothetical, but I do want to make a couple of things clear in case somebody just runs with your idea.  

Reliable STD testing takes up to several days to provide the results.  Clinics advertise "same day testing", but all that means is you go in without an appointment and they take your samples right then and there.  THEN they send the samples in for testing at a lab, which takes 24-48 hours or more to provide reliable results.  So, you'd have to keep the lady under surveillance (take her on a platonic vacation with you?  Watch a TV marathon together?) for days to make sure she doesn't see anyone else.  Not sure how that'd work out.  

There are a lot more complexities to it, like you can catch Herpes even with a condom through skin-to-skin contact, Chlamydia can take weeks after exposure to show up in a test, and so forth.

Best bet is to educate yourself and try to minimize the risks, but be aware the risks are always there.  

Good luck, stay safe