What is the difference between the financial requirements of a retirement visa and a marriage visa in Thailand?

The retirement visa in Thailand requires proof of 800,000 baht in a bank account for a period of two months before the application and three months after, before dropping to 400,000 baht for the next seven months. In contrast, the marriage visa requires only 400,000 baht for a similar duration prior to application, and this amount can be spent once the visa is approved, with a ten-month period before needing to restore it to the minimum requirement.