I am a bit of a collector and it is strange what I find will hold up. And sometimes items that seem like they will last forever are the first to go. The wooden box referenced earlier is a great example. I have seen pristine crates, cigar boxes, and paper wrapped items utterly ruin its contents. I also have an old mapcase that has nearly perfect leather, but all the metal fittings, even the ones not in contact with the leather, are junk. I would love to use it, but I just can't bring myself to replace the hardware.
And if anyone needs to rotate out some old "useless" ammo let me know! I have some WWI era .303 that went bang every time (before I found out it was worth $) and I routinely fire 60 year old Turkish and German 8mm, not to mention 40's and 50's era 7.62x54. I can guarantee you they were stored in some nasty hot/cold conditions but as long as there is no serious corrosion it is fine.