Do I need to show 400,000 BHT every 90 days after obtaining a one-year family visa in Thailand?

Once you are issued a family visa for one year and have demonstrated the required 400,000 Baht in your bank account, you do not need to maintain this balance during the 90-day reporting. You can withdraw the funds, but you must restore the balance to 400,000 Baht two months prior to your next extension application.