Leon wrote:

Storage conditions will factor in with each set of circumstances.
As for your 18 year old glue, it is too early to tell if it is still OK or
not. You may have tested it by doing a glue up and it appears fine but glue
deteriorates over time any you test piece may not hold up. It could
possibly fail in 10 years. Glue is CHEAP and it should hold your projects
together long after you are gone.

I have Weldwood Plastic Resin glue, Elmer's carepenter's glue, and
Elmer's resorcinol glue that are old. None give a shelf life on the
container. I think I saw 1 year for Plastic resin (a powder). In any
case, all have been used long after they were purchased and continue
to performed as expected. There is no reason to believe that glue
will fail some time after the application if it doesn't fail
immediately after or during application. All glues probably fail over
a period of time and under adverse conditions.

The world is so full of crap about products and applications that it
is difficult to know what is true, but some is such obvious bull****
that you wonder why people believe it. As an example, periodic wheel
alignment. Wheels are either aligned or not, and the only way to
become unaligned is to bend, break, or wear out a part. If you don't
need a new part for the alignment then you didn't need an alignment or
more likely it wasn't aligned correctly the last time.

Because some things do need periodic maintenance and some things do go
bad after a period of storage, it is easy for manufactures to prey on
the gullible by insisting on certain periodic maintenance and on
replacing older products.

A 1 year or six month warranty (or shelf life) is probably more about
legal protection and a desire to sell more product than any truth
about the product.