How can I choose the right agency for obtaining my retirement visa in Thailand?

You don't.

Immigration office will handle all your needs for princely sum of

@19**

Why don't you just walk into immigration they're most helpful

Go thru the threads to find agencies that have decent reps. However, it seems using an agency comes with risks.

1). Appears you end up tied to one immigration office. If you move that can be a problem

2). You’re handing over the whole bank guarantee process to the agent. On the face of it this doesn’t seem wise and creates opportunities for all manner of risk if and when the government does one of their periodic immigration crack downs.

You can do all of this yourself either by getting an O A in your home country or getting an O after arrival. There’s a bit of running around, printing, stamping and signing but IMO it’s worth it

Ask somebody bro

Thai Visa Centre

The best agency to use is either the online evisa portal or your local immigration office in Thailand depending on your location

If you know which city you want to live in look for Facebook group in that city and ask for referrals

If you meet the requirements, do it yourself ?

How do you find a company to do business with for any service? Do research, ask for referrals, read reviews.