I'm in Nakhon Sawan and today went to immigration to check on requirements for the 90 day registration. I have read alot about requirements so a month early I wanted to check what they would ask for being a new process.
So I'm with my thai partner and they explained in thai and repeated in English that so long as my TM30 was registered (which it is) I need not do anything else.
Advised that after 180 days to either leave the country or extent, which I knew.
To extend she advised I would need to present the same proof of funds I obtained the visa with being the 50,000tb (or equivalent to what was requested upon application) mine being ยฃ11,000
All in all very simple and pleasing.
Hope this helps.
Sure other provinces are different in some way.
Enjoy