Does anyone here think small lfs
ever rotate their dry filter media stock and throw things out just because they are a few years old?
Carbon and zeolite don't really 'go bad', but they can pick up toxic chemicals and mold spores if they were not stored properly.
If they were sealed in a closed box and kept in a cool, dry place, good.
If they were kept in an uninsulated attic or basement and subjected to moisture and temperature swings, bad
If they were kept somewhere they could pick up toxic chemicals (garage, near household cleaners, etc), bad.