What is the validity period for a bank letter when applying for a 1-year Non-O extension based on marriage in Thailand?

When applying for a 1-year Non-O visa extension based on marriage, the timing for obtaining a bank letter varies by Immigration Office. Some Offices may require that the bank letter or statement is dated on the same day as the application, while others accept documents that are up to 7 days old. It is advisable to go to the bank a few days in advance to request a 12-month statement, as 6-month statements can usually only be retrieved directly from your branch. Additionally, some applicants have been asked for a bank guarantee certificate as part of their application.