Do I need a TM.30 every time I leave and re-enter Thailand to extend my visa exemption?

If you don't have a tm30 for your current stay, ( meaning when you entered Thailand this time and did not report your address)

Then when you go do your visa extension the imm will issue a fine of about 2000thb for not reporting your address, the fine will actually be issued to your landlord,

After the fine is paid, they should allow you to do the extension,

(Note the extension will be 30 days as it's your first extension this year, later this year if you want to extend on another entrance visa you will only be issued 7 days)

You mean you need a new tm.30 everytime you arrive. Yes, once you leave, your tm.30 is finished. If you entered again, and didn’t apply for a tm.30, then you don’t have one. Also, this is a page for the DTV visa, not visa exempt or other visas. Suggest asking only DTV related questions here

You’ll need an updated TM.30 address registration receipt when you apply for an extension. If you leave the country, you will re-enter on a new visa exemption anyway, as the previous permission to stay is cancelled upon departure and can no longer be extended.