I have done my own marriage and then retirement extension for over 30 years, but it takes so long, even when I have an appointment. In 2023 I arrived at Chiang Mai office at 9am with my papers, they were checked and I got a queue number. At 14;30 I had my photo taken, and my passport was returned at 15:20.
In 2024 I used an agent. I gave the agent my passport and bank book, and paid the fee, 3,500 baht plus the 1,900 Immigration fee. They took the photos, and told me to meet the agent at 14:15 the following day at the Immigration Office. I met the agent at the Immigration office. The photo was taken, and immediately my passport and bank book were returned with the new extension. Time in the office less than 5 mins.
I paid for the convenience.