I had an OA visa, obtained from the LA consulate, for 6 years. I now have a 10 year pensioner LTR visa.
One other option is the 10 pensioner LTR visa. This requires health insurance (with some lenient options) and a passive income of $80,000/yr. If you think this might be of interest to you then look for it on the Thailand Board of Investment (BOI) website.
These days I would recommend you come to Thailand and obtain a non-immigrant O visa. That is a 90 day visa and then you get 1 year extensions of that visa indefinitely. It does not require insurance. I, of course, recommend having insurance but if it isn't tied to your visa then you have more options. You will have to maintain 800,000 in a Thai bank to get the 1 year extensions of an O visa.
You could go ahead and get an OA visa. An OA visa will require you to maintain Thai health insurance for the visa and subsequent extensions. You can qualify for this visa with funds in your US bank accounts but extensions of this visa will require 800,000 baht in a Thai bank. It is a one year visa that, like the O visa, can be extended 1 year at a time indefinitely.
The OA does have a weird benefit that if you leave and return within the first year of the visa you will be stamped in for a full year (or until the end of your insurance policy). This means if you time it right and you have the insurance you can get almost 2 years on an OA visa before you have to start extending it in Thailand or return to the US to apply for a new OA visa.
I know how to get rid of an OA. I’ve seen Tod address this issue with the opposite results you describe. I’ll go with whatever Tod says but I suspect the OP will go with a non-O to begin with. That’s what I would suggest these days. I went from my OA to an LTR a year ago.
I am not suggesting changing the reason of the visa. However you can choose retired or married for the visa 1 year extension after the first extension. I could extend my OA visa as married if I chose to. I’m happy to let Tod weigh in on this.
First your age is going to matter and expect that preexisting conditions won’t be covered on a new policy. My strategy was to buy into a policy with a large deductible (40,000 baht in my case) which will lower the cost. Pay for routine care yourself. Keep money in savings ($100,000+ ??) to pay for what the insurance won’t cover. The insurance is for a catastrophic health event. If you are over 70 then any new insurance may be a problem.
At first an OA visa requires health insurance. You will have to do this the first year. If you have then extend your OA visa for 1 year as married then, I believe, you no longer need health insurance. Check the details on this with Tod Daniels in this group or the Thai visa advice Facebook group.
If you extend an OA visa as retired then you need insurance. If you extend as married, I don’t think so.
You do have to return the proof life form. If you are using a US address then you have to know it arrived and have it forwarded to to you. I’ve never seen an option to submit the proof of life online. Some people will already be receiving SS in the US and then move to Thailand. Once someone gets settled here the it is a good idea to tell SS your new Thai address. Social Security totally supports Americans living long term overseas. Expats in Thailand are supposed to use the Social Security office in Manila, Philippines. That’s the office to which I send my Thailand address changes. Strangely though the proof of life letter must be returned to the US office using the envelope provided. I go to the expense of sending it using the Express Mail Service (EMS) which will also track the letter.