When should you switch from a retirement extension to a marriage-based extension of stay in Thailand?

You can choose not to switch from an extension of stay based on age (over 50) to a marriage-based extension. However, marriage extensions are generally considered less cumbersome. Your current extension remains valid until the expiry date stamped in your passport. If you decide to switch, you can apply for a new extension based on marriage at most immigration offices, starting 30 days before the current extension's expiry date.