The experts will tell you that house paint is only good for 5 years too but I've used stuff that was well over 20 years old (possibly over 30) with no problems, both alkyd and latex.
I have a feeling that a lot of the shelf life recommendations for things like that are very conservative and based more on liability concerns than actually unsuitability for use.
It's a lot like the "best before" dates on food. I know people who won't eat anything that is even a day past the BB day but the key is that it says best before, not rots after.
I'm with you on this Bob. I've been using the same tapping oil bottle for more than 20 years now and don't feel bad about it, same thing for my chainsaw's bar oil gallon which must be more than 15 years old. Gear oil for my snowblower auger worm drive is pretty old too. Those applications aren't really critic so I have no worries about using old stuff.
That being said, I woudn't use 15-20 years old engine oil in anything but a lawn mower, additives degrade with time and wearing out an engine or transmission because I cheaped out on oil makes no sense. Oil technology also improves so I want to take advantage of the new products available.
On the other hand, there is stuff that has a definite shelf life, like brake fluid (especially if opened).
To finish, my worst experience with an expired product has to be shower and bathtub silicone caulking. I once redid the shower's caulking using a tube of GE premium grade silicone caulking I had laying around. A day later it hadn't cured at all. I thought that was strange but decided to give it time, we had a 2nd shower so no big deal. A week after there was no change so I had to remove it all and start over... Took me a day to clean up properly and redo, it was as if I had caulked with thick grease... Found the tube in the trash and indeed there was an expiry date on it, and I was past it by a few months... Now I just dump what's left of the tube when I'm finished, I don't want to ever do this error again!
