As I understand it, the " porous filter medium consists primarily of microscopic cellulose fibers along with synthetic fibers such as glass and polyester, which increase filtering efficiency and durability. The medium is also saturated with resin to give it strength and stiffness. Higher-grade filters have more synthetic fibers."

tinyurl.com/y73ow64f

So if it has been stored in perfectly dry conditions in a temperature range of say 5C to 60C there will be unlikely to be much degradation in the filter medium. But if exposed to UV light - out of packaging - the seals may gradually stiffen and lose elasticity.

I would say 10 years tops.. But as the risks from a failed filter are so high - eg engine ruined - I would suggest 7 years tops..

Personally I would sell them ..

Well it LOOKS like a conventional filter, though I dunno what's inside that particular make. Conventional filters are paper-based, though higher end ones have synthetic fibres.

Ordinary paper suffers slow acid hydrolysis and oxidation, which is why old books/newspapers look brown. A lot of the acid is in the paper from the start, though, which may not apply to oil filter fibres.

You could probably largely prevent breakdown by pre-oiling the filter. This will largely exclude atmospheric oxygen, humidity, and pollution, and the base in the oil will probably neutralise any acids. If you've got the filter full of oil, you'll have to store it upright in a well sealed container to avoid mess, adding another layer of protection.

Stored thus, I'd bet it'd last for decades.