When extending a visa in Thailand, particularly for retirees, it is crucial to be aware of specific documentation requirements that can vary by immigration office. Many expats have noted that the bank letter must now be dated the same day as the visa extension application, which can be inconvenient. Additionally, some offices may require further documentation like the landlord's ID or tax ID if the landlord is a foreigner. It is recommended to check with the local immigration office just before applying to ensure you have the correct and up-to-date requirements, as they may change yearly.