When do I need to show the affidavit of income for my non-O visa in Thailand?

Good for 6 months, and mine took 7 days,they also mailed it to my address in which I was going to reside in Thailand. Good luck.

𝗪𝗵𝗲𝗻 𝗱𝗼 𝗜 𝗻𝗲𝗲𝗱 𝘁𝗼 𝘀𝗵𝗼𝘄 𝘁𝗵𝗶𝘀 𝗮𝗳𝗳𝗶𝗱𝗮𝘃𝗶𝘁?

you will show this affidavit when you apply for the initial 90 day Non-O visa

AND (45-60 days later)

you will show it again when you apply for the year extension

𝗮𝗳𝗳𝗶𝗱𝗮𝘃𝗶𝘁 𝗳𝗿𝗼𝗺 𝗖𝗮𝗻𝗮𝗱𝗶𝗮𝗻 𝗰𝗼𝗻𝘀𝘂𝗹𝗮𝘁𝗲 𝗶𝘀 𝘃𝗮𝗹𝗶𝗱 𝗳𝗼𝗿 𝗼𝗻𝗹𝘆 𝟵𝟬 𝗱𝗮𝘆𝘀. <- That is bad information, affidavits of income from abroad notary letters (for the consulates that issue them) are valid for 6 months from the date they're issued.

Some offices will copy your original embassy affidavit and stamp it so you can use that copy when you apply for the year extension,

BUT

some do not, meaning you get one to apply for the Non-O visa and then have to get another one to apply for the yearly extension (no issue getting them bothat the same time)