Difficult to say. We have some materials in our lab which still print fine after 5 years.
Our materials have a long shelve life depending on the environment the material is stored in. We recommend a dark and dry storage box, away from direct sunlight and free of dust. Materials can be stored for a long time, 18+ months and can be dried if necessary.
NOTE: Keep in mind that our steelFill, copperFill and Bronzefill have a shorter Shelve Life (>2years) because of the metals in the PLA filament which oxidize a bit quicker.
Please revert to TDS documents for each material to find recommended drying temperatures and time.