Do I need to ensure a TM30 is filled out every time I leave and return to Bangkok during my two-month stay?

Yes of course, but why would this be a problem? It's routine.

Hotel should do it

Also in the interests of clarity, if you stay for “two full months” (without an extension) you will overstay. Your visa exemption period is 60 days (59 nights). People have reported getting caught out by this before. Good luck.

Kap

Fugettaboutit

NOPE

The answer is the same as in your last post.

IF you are only staying in Thailand for 2 months, and will not be going to immigration for anything, including an extension, you never have to worry about TM30 at all. The ONLY time a TM30 is required is when you are going to immigration for something. If you're not going to immigration, you don't need a TM30.

It's the property owner that is legally required to file a TM30, so it's not your concern at all. Unfortunately if you go to immigration and one wasn't filed for you, immigration will penalize you rather than the property owner. But regardless of that, if you're not going to interact with immigration, TM30 should not be on your mind at all.

IF you DO plan to go to immigration, the only TM30 that matters is one filed for where you are currently staying at when you go to immigration. Any TM30's that were or weren't filed before that don't matter at all. TM30 is about where you are staying NOW, so that's the only one you care about.