I keep 800,000 baht in my Thai bank year after year because it is simple to do and I can afford to do it. I don’t have to track whether I made a deposit each month and more importantly whether each deposit is tagged as a foreign transfer. I never have to think about meeting the financial requirements. I think the key factor here is that some of us can afford to keep the money “tied up” and we consider the monthly method too much of a hassle.
They are just pages printed by the bank. Nothing complicated about it. That is what staples are for. It is true though that there is less chance of accidentally dipping the balance too low. Never been a problem for me.
A bankbook is not a reliable statement of the year banking activity. I literally never update my bankbook except on the day of my extension application.
It is a small charge and my Kasikorn branch provides a year statement while I am sitting there. Others though have to wait several days. Best to know now your particular bank’s procedure.
All of this points to the wisdom of applying for your yearly extension as early as your immigration office allows, 30 or 45 days. If you have never obtained a yearly statement then just get one now to familiarize yourself with your bank’s process
90 day reports are free and you can do it in a 3 week window from 2 weeks before it is due to 1 week after. If you are going to be in the immigration office anyway then just ask or just do it.