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 £11,000
All in all very simple and pleasing.
Hope this helps.
Sure other provinces are different in some way.
Enjoy