Useful suggestion for those staying in different hotels around Thailand:
To avoid TM30 and 90-day report problems, use your driving license as ID for hotel check in ..
always works, but not matched or updated by immigration, so the address used for 90-day report stays the same.
Presumably, work permit would be OK too (worked once to catch a flight :-)).
I discovered this by accident, so I hope it still works!
Jim