Hey! Rob,
You mean your pictures have a use-by date? Mine are forever .
I used to think the same of mine, until this afternoon. I had scanned and then lost (in the machine) an image I'd take of my wife on our honeymoon, a Kodachrome of some sort -maybe an X (the Kodachrome, not the image, I never played that arena) - and when it showed up again in that mystery Photoshop folder I had never created, I seized the opportunity of opening it and instantly saving to my usual folder for such things. So, I spent much time playing about with it and discovered two things: she was more beautiful than I'd ever thought at the time; Kodachrome does go off, physically as well as colour.
On the other hand - there usually are two - I found that the slide had been kept in a slide frame that was enclosed - either thin plastic or glass, I threw the original frame away without thinking to find out which - and it now sits reframed in glassless Gepe within an archival Diane Wyllie Viewpack. I still have hundreds that will probably turn out to be valuable some decades from now. The unused ones, that is. Perhaps the imaginary safety of protective glass was quite illusory and more damage done than prevented.
So, your claim might play better as a James Bond title than snapper reality...
;-)
Rob C