Not dengue fever. You can’t get that one until you’ve had dengue once. Get a flu shot, a Covid shot, DPT and a Japanese encephalitis shot. Stay away from monkeys and dogs once you get here and you won’t need the rabies shots.
Save all receipts from visa purchases, 90 day reporting proofs, airline ticket stubs, apartment rental payments because you might be asked someday to prove how you got in to Thailand. Take these with you when you go to immigration to get your retirement visas granted and also when you renew a year later.
I found that it took attention to detail and a mountain of paperwork to be able to get in and stay in over the last 2 years.
Also, get three power strips that are able to handle 110v-240v simultaneously from Amazon. The ones we got are from Superdanny, have six plug spots and 4 USB charging spots on them. Very difficult to find these things here and we found them to be the best things we brought from the USA.
I had a reservation with Agoda where the hotel decided to close for maintenance. Agoda didn’t help me but the staff at The Sukosol in Bangkok arranged with The Pullman around the corner to take my reservation at the same price.