I'm on a retirement visa and new rules say , when U take Ur bank book to do Ur visa or visa renewal , the 800k HAS to be visible in ur bank 2-3 prior and 2-3 after , any other time it doesnt need to be there but i did hear it cant go below 400k so u need to check on that.
This stops the agents depositing the cash for u then 5 mins later returning it.. cos they are trying to by pass it.
Thailand don't want the poor in and they see 800k a year as acceptable.