What are the TM30 requirements for returning expats with a non-O retirement visa in Thailand, and when can I apply for a visa extension?

𝟭. 𝗵𝗮𝘃𝗲 𝘁𝗼 𝗰𝗼𝗺𝗽𝗹𝗲𝘁𝗲 𝗮 𝗿𝗲𝘀𝗶𝗱𝗲𝗻𝘁𝗶𝗮𝗹 𝗳𝗼𝗿𝗺 𝘁𝗺𝟯𝟬 𝗻𝗼𝘄 𝗲𝘃𝗲𝗻 𝘁𝗵𝗼𝘂𝗴𝗵 𝗺𝘆 𝘃𝗶𝘀𝗮 𝗮𝗽𝗽𝗹𝗶𝗰𝗮𝘁𝗶𝗼𝗻 𝗵𝗮𝘀 𝗺𝘆 𝗮𝗱𝗱𝗿𝗲𝘀𝘀 ..𝘀𝗮𝗺𝗲 𝗮𝘀 𝗶𝘁 𝘄𝗮𝘀 𝘄𝗵𝗲𝗻 𝗶 𝗹𝗲𝗳𝘁 𝗧𝗵𝗮𝗶𝗹𝗮𝗻𝗱 𝗹𝗮𝘀𝘁 𝘁𝗶𝗺𝗲

That is an immigration office specific policy, SOME offices make you re-file or at least update the TM30 when you come into the country even if you're returning to your primary address, BUT

Some offices say as long as you're going back to the address where you were previously registered you don't need to

Sadly (for you) the only way you will know is to slog on over to your immigration office and ask OR just file a new TM30 to be sure

𝟮. 𝗪𝗵𝗲𝗻 𝗰𝗮𝗻 𝗜 𝗮𝗽𝗽𝗹𝘆 𝗳𝗼𝗿 𝘃𝗶𝘀𝗮 𝗲𝘅𝘁𝗲𝗻𝘀𝗶𝗼𝗻 𝗳𝗼𝗿 𝘁𝗵𝗲 𝗻𝗲𝘅𝘁 𝘆𝗲𝗮𝗿𝗹𝘆 𝘃𝗶𝘀𝗮

Most offices let you apply for a new extension when you have 30 days or less left on your current stamp (Bangkok, Chiang Mai, Buriram and Phuket) allow you to do it when you have 45 days or less left on your stamp.

I'd use 30 days or less as the rule and that means you can file any time AFTER Mon 26th Feb