For O-ring storage, just Google "o-rings long term storage".
I came a cross a few posts. Basically it depends on the materials they are made from.
Now if only O-ring kits detailed what the O-rings were made of, we would be in good shape.
Below is copied from an O-Ring dealer...
Recommended Shelf life
- 5 years: Polyurethane (millable), SBR, Natural Rubber, Polybutadine, Polyisoprene
- 15 years: Nitrile, Neoprene, HNBR, Polyacrylate, Butyl
- Unlimited: Ethylene Propylene, Fluorocarbon, Perfluorinated Elastomer, Silicone, Tetrafluoroethylene Propylene (Aflas®), Fluorosilicone.
I bought a Jansport backpack around ten years ago that had some high tech silicone 'waffle' padding in the shoulder areas.
I remember that they had a store display where you could see and feel some of the silicone waffle - just felt like normal silicone rubber as used in cheap phone skins and o rings.
One day I noticed that there was sticky stuff all over the shoulders of my shirt.
Turns out the silicone had turned into a thick syrupy liquid and oozed out through the weave of the fabric onto my shirt.
I don't know if it was heat, UV light (the straps had transparent 'windows' so you could see the waffle inside), or simply mechanical pressure that had caused them to liquify, but it happened.
Considering Jansport has a lifetime warranty against defects in materials or workmanship, I'd say that they were expecting the waffles to last pretty much indefinitely.
That reminds me - I still have that backpack somewhere. I'll have to dig it out and see if I can get a replacement...