Will drop in liners get brittle over time?

[Snow mom]

I have an extra, unopened box of drop in liners. I'm giving away some of my other drop ins things (10 oz bottles that were never used and liner samples that came with them.) I'm wondering if it's worth it to hang onto the unopened box for any future DC (2 years from now at least) or whether they will be worthless by then. Anyone ever opened an old box of drop ins?

[SnuggleBuggles]

My friend gave me some of her's that were 2-3yo and they were still fine.

Beth