ReEntry - you do need to purchase a ReEntry permit before leaving Thailand to avoid cancelling the Visa (even if it says multi entry). The permit can be single or multi entry and is good for the term of your Visa. typically purchased at airport when leaving, but suggest checking at your local immigration office in advance in case anything changes with the rules.

I have OA

- must move 800K to Thai bank after arrive, must be seasoned in Thailand bank before one year Renewel.

- must do 90day reporting, in person each time address changes, on line reporting ok if stay same place. 90day counted from latest entry to Thailand. Penalties if late so best do a week early.

- renew annually in Thailand at nearest immigration.

- immigration pretty quick and easy in smaller cities, but crazy lineups in places near Bangkok so beat allocate at least a day. My first 90day took 1.5days in Joetiem, as I also set up my banking

- recommend get account at two banks in Thailand in case one banks services not available sometimes. Also keep 3-5000baht in cash as sometimes can't access ATM, or Pay by QR not work in mountains.

- do set up pay by QR on bank app as used everywhere in Thailand, even food stalls

- do set up an online phone number in home country well BEFORE LEAVING for doing home bank verification, etc. Put as second number in online accounts. This just makes using home bank so much easier (transfers, Wise, Income tax, etc,). Ask your fellow countrymen which service best for your country. Something like Tossable Digits.

Always do early, I'd never go after the stamped date, sometimes something goes wrong and you need those extra days to fix things.

Update your bankbook at ATM and bring it too

I was told you can do online reporting if your address hasn't changed since last report. Foreign travel can mess that up.

Travel around, find a place you are happy. Do your 90day at closest immigration office (or online if no address change). Ive been alternating staying a few months, then travelling a few months for 2 years with no issues. It's fairly common to move around on OA Visa till you find your new "home", if ever. Settling for few months sometimes gets better rental rates.