Do I need to obtain a 400K bank certificate right before applying for a marriage visa in Thailand?

The timing for obtaining a 400K bank certificate for a marriage visa in Thailand can depend on the specific immigration office. For example, in Bangkok, the certificate is valid for up to 7 days, so it doesn't have to be obtained exactly one day before applying. However, it's important to also have your bank book updated on the day you apply for the visa to verify the balance.