The LTR is 50,000 baht for 10 years. Hardly expensive. You may be thinking of the Elite visa which is pretty pricey. While the LTR isn’t expensive to obtain you must have $80,000/ yr passive income to qualify for.
I found immigration in Bangkok to be very organized and professional. They do everything by the book. I did my OA extensions there for 6 years and never had a problem. I found no need for an agent.
You stay 6 months. Then you can extend 6 months in Thailand at the Immigration Department one time. I’m not sure what the Immigration Department is going to ask for an extension.
If you can do it yourself and they want 5k for insurance then that sounds like a bargain compared to an agent. I bought the insurance at Kasikorn. It’s real insurance. A couple of months later I had an accident and Kasikorn paid the 5k promptly.
You become a tax resident in Thailand if you are in Thailand for 180 days. Starting in 2024, money brought into Thailand is taxable. It is hard to say what this means until Jan-Mar when we can see the Thai tax forms. Thailand has dual tax treaties with many countries. For US citizens federal pensions such as Social Security are not taxable in Thailand. You would have to check the tax treaty details for your country.
If you have a pensioner LTR visa then money you bring into Thailand is not taxable.
Another perspective is to go as early as possible which would be 30 or 45 days depending on your immigration office. Ask your question and then bring everything that is easy to do. It’s a lot easier to bring too much than not enough. If they don’t want it they won’t take it. If you don’t have something then you have plenty of time to get what you need and return another day if that is necessary. Take notes. Next time you will know what you need to know.
The US embassy no longer provides residency certificates.
I was able to get both my Thai drivers and motorbike licenses using my California drivers license. No IDP. I didn’t have to take a road test or the written test. This was at the DLT office at Bang Chak, Bangkok.
I got my medical certificate at one of the small medical clinics.