How long will a ceramic coffee cup last outdoors? That should be pretty much how long Cermark will last--

FWIW, I Cermarked a pair of dog tags for our mutts 8 years ago. Dijon's tag has been rubbing against an engraved aluminum tag the whole time...

The Cermark that has been rubbing the aluminum tag is gone. However, so is the engraving on the aluminum tag--it's almost completely smooth! They both wore each other out...