Are NOS phono cartridges best avoided?


I have read that the compliant suspension components in phono cartridges are subject to deterioration/hardening as time passes. Is this strictly a function of time or does exposure to atmospheric conditions and polutants factor in significantly? I occasionally see "new old stock" cartridges for sale/auction that were good performers at the time of manufacture 10-20 years ago. Are these best avoided or are they still useful if they have been sealed in factory packaging? Anyone have experience with this sort of thing? Thanks, Will.
photon46
Most cartridges do suffer a "shelf-life" effect. This is due to the suspension loosing compliance because the elastic material ages when exposed to the atmosphere. I suspect that storage in the correct inert gas environment could extend this, however, I doubt that anyone has gone to these efforts. I would consider a cartridge that has zero running hours and a moderate age (perhaps up to 5 years) a purchase option, but would avoid ones that are considerably older.
I have gotten several of the old GAS "Sleeping Beauty" MC cartridges for $50 a pop. I love'em, they sound great, and I have had no problems whatsoever. When new, they were around $150.