I’ve basically been doing three exempt visits a year or one 60-day visa and a couple of exempt visits since 2018, and have never had an issue beyond being asked to show my outbound ticket. But on my last entry in Bangkok in June, the immigration officer spent a long time looking over all the stamps in my passport and my flight reservations on the Trip app before she let me in. So, I decided to just go with the multi-entry tourist visa for $200 and use it for a couple of 60-day entries and one 30-day — basically the same 5-month itinerary you’re aiming for. If the $200 isn’t an issue, then I think the tourist visa might be an easier application than the retirement visa. But I’ve never tried the retirement visa application. I don’t want to admit I’m old enough! :)
back before the switch to 60-day exempt, I used to get a tourist visa, do a border run to Vietnam, and then come back to Thailand for the 30-day exempt (and then leave for Indonesia and come back for another 30 days a month later). So, I think you'd probably be fine. The one concern I'd have is that people have been reporting challenges when they try to enter repeatedly with an exemption now, especially if they've done extensions in the past.
Personally, I decided to just do a multi-entry tourist visa for my upcoming trip, so I won't have to stress over it. The consulate in HCMC took 2 business days to get back to me with a request for a newer photo and an itinerary (I had only made reservations for my first 60 days of flights and hotels), and then took another two business days to approve me.
So, if you're just doing one exempt entry, I doubt you'll have any issues (but I'd defer to the experts). If you're planning multiple visits after, I think you can take the anxiety out of the process if you do a border run to HCMC, apply for a tourist visa, and include a proposed itinerary in the PDF of your plane & hotel reservations.
I wouldn’t hesitate to get general dental services in the Land of Smiles. A lot of Thai dentists trained in the U.S., and I think a fair number will also have done training in Japan, Australia, and Europe. Equipment tends to be first class as well.
If you have sleep apnea (or a bad snore), Bangkok Smile (near the Asok MRT, if memory serves) is a really good place to get a mouthpiece for sleeping — one of those thingies that holds your lower jaw in a forward position while you sleep, so the airway is unobstructed.
In the U.S., that tends to be something medical and dental insurance will go back and forth on for months, with each denying they’re responsible for paying for anything. In Bangkok, since you’re paying out of pocket, you can just skip all that nonsense and get straight to treatment.
They’ll do a 3D scan of your teeth, send it to a facility in Germany to custom print your mouthpiece, and then have you come back a week or two later to pick it up and make sure it fits. When I’ve shown the result to dentists in the U.S., they tend to say things like “That’s better than what my husband has,” and then, once I tell them what it costs in Bangkok compared to New York, they start planning a family vacation to Thailand.
as a solo traveler, I’ve found that it’s pretty easy to make friends in Thailand just by exploring the local coffee scene instead of drinking coffee in my hotel. Look for a cafe where you can actually sit or stand at the counter and chat with the baristas, and they’ll remember you the next time you visit.
House of Supha in Talat Noi and Old Town Cafe in the old city are especially great for this, but as a stylist staying on Sukhumvit 11, you might really like Sometimes I Feel on Sukhumvit 31. The team is very nice, and the place manages to be stylish, vintage, a little nerdy, and like being in a friend’s living room at the same time. I’d trust them to know some great stylists, or have stylish friends with great hair who are open to helping you out.
I sometimes ask baristas to tell me where to go for food, and to write down in Thai what to order. And places where I might otherwise feel totally intimidated by the language and cultural barriers just start smiling when I hand over a slip of paper. I bet you could do that with hair, too, although I think you’ll find that many of the experienced stylists are pretty comfortable speaking English.