Been like you travelled quite a lot to Thailand as an ex. offshore worker by visa exempts with or without 30-days extensions. But also with have Non O-A Multiple Entry 1-year Visa (before the insurance requirements to have to be insured with a Thai insurance company came to force).

As you are 50 years old a Non O 90-day e-visa as retired could be a good start as travel to Thailand with. As step two do an 1-Year Extension of stay based on retirement and buy a multi re-entry permit which will give you the option to travel out/in of Thailand as you wish.

I have a health condition to which might be difficult to get a health insurance for in Thailand to cover for. I and my Thai wife spend like 50-50 in Thailand and Sweden and we are officially registered as living in Sweden. I do purchase ”extended travel insurance” via the insurance company I have my house insured in Sweden. The extended travel insurance takes over after the the common travel insurance of 45 days has past in case with the insurance company I have. The insurance company like most other Scandinavian insurance companies are using SOS International in Denmark as the contact center. I have checked with SOS that my condition is not considered as will hinder me to be free to travel as I like and without limitations for health care in for example Thailand. SOS prefer to use Bangkok Hospitals when possible. The extended travel insurance has had to be paid and registered prior to I travel from Sweden. But if decide to stay in for example Thailand longer than I originally planned it is possible to extend it as long as it’s done and paid for before it has expired.