if you’re studying Thai.. fill in your arrival card in Thai. Proof of study 😉

Let the school know of your travels too. So they can get extensions for you. Usually it’s ok for short trips.

You should always have a general plan for what you will do for 30 days in Thailand just in case. And also a plan for leaving when your exemption is finished within that 30 days.

BUT You won’t be asked anything by immigration unless they suspect something. That’s where your plan comes in.

Your airline will most likely ask (particularly budget airlines) about your plans if you are on a one way ticket. Sometimes they won’t even ask for proof and just accept what you say (see the plan part)

Sure you can try updating and see if they say anything like “sorry already done”

Chiang Mai no you don’t. Only update if you leave the country (no need to do a new one)

Multi entry tourist visa is another option for 6 month visits. And you don’t need to keep as much money .

If it’s not ok they probably won’t let you out unless you have to get a full Myanmar visa.

Just take the receipt with the updated departure cards and get it updated.

You can still get proof but it's just a bit harder

You show an updated Bank book in your name. What you do with the money after the extension Is granted is up to you