This is more a philosophical query - is there a shelf life for strings - ie, banjo, guitar, mandolin, etc. ?

I wondered about this last night when I hauled in a new batch of strings I had ordered and forgot in the back seat of my car for a day. They were pretty hot and I wondered if the heat had taken anything out of them.

Also, a number of years ago I inherited my wife's grandmother's old potato bug mandolin and with it a mint tin full of strings from around 1910. I was never very sure about their quality - but at that time I was a rank beginner.

So I'm wondering. Do strings age just sitting around, and can extreme heat or cold storage factors affect them, or do they keep their "zing" until used ??