@Jack *******
we have to the report every 90 days, 1st 1 in person in your nearest immigration office and then ones after can be filed online. I asked my nearest immigration office in BKK, and they said I must do a 90 day report. Make sure you get a Tm30 from whoever you are renting from.
If you leave within 90 days, no worries, it's just when you complete a full 90 days, it's gotta be done.