I once told a small child in perfect Thai that we were going to eat lunch. She ran screaming back into the house and would not come out. Her mother explained that she had interpreted my Thai for I am going to eat you for lunch. True story. The kid still wont have anything to do with me 4 years later.
I tried while on Phuket but it just would not work. I believe it is because my current tm30 did not concur with my home province. I had to do it in person at Bangkok which caused ructions on my next visit to local IO as I had not reported to them again! I will give it another go next time but my tm30 has to be up to date.
It varies from office to office as stated. My office has just started to insist on a fresh tm30 even after one day away if it was registered. If you stay in a hotel or guest house it will be registered. I have registered the property I live in myself at tm30.io and I can now register tm30 on line by uploading a copy of my passport each time I return home.
if you are long term in Thailand you must report every 90 days to your local immigration office or on line if it works. If you leave Thailand your 90 days starts again when you re enter.
if it was easy everybody would do it. The system frequently does not work. If it works for you you are lucky. It has only worked for me since in r years.
0 in a thai bank account for two months. That is how it works in most places and certainly for me. In fact, my office insisted on 3 months prior to renewal.