maybe for where you are. Where I live immigration turn up and take photos and ask neighbours if you really live there and socialise with them .. and that’s on a retirement extension
Passport , proof of residence, Thai phone number, copy of visa/ work permit , anything else you can think of. You may have to try quite a few banks and even branches of banks to get one.
Usually 30 be prepared for some interesting new requirements. Some immigration offices now give a 30 day under consideration stamp and insist on house visits to check you actually live where you say.
They will do home visits every year during the 30 day consideration period for marriage extensions and more and more provinces are doing home visits and giving 30 day consideration periods for retirement extensions. Just means they are being more thorough on what they do. This has been coming for a long time… don’t expect the rules to get easier
Bank letter maximum 1 week. 800k in bank minimum 2 months before your application date. Cannot drop below 800k for 3 months after and never go below 400k even for a nanosecond. Bank book updated on the day.