For those who are not aware, Propane tank expiration.

Around here places that re-certify cylinders are getting rare; I finally found a welding supply outfit that does it. I'm left with little choice in my case (and maybe some of you) since the cylinders in our TT are designed to lay down (horizontal) while in use and have proprietary brackets welded on the cylinder for clamping down when in place. It's worth some phone calls - unless these places get patronized they will eventually disappear altogether.