I have a bag of wads I purchased last fall as part of a Craigslist ad for a reloader.
These are Federal, "Pushin Cushion", 12S1 wads, from probably the late 70's early 80's.
I'm pretty sure they weren't stored with any eye to the future and saw their fair share of seasonal New England cycles, based on the condition of the reloader. The wads in the top of the bag are brittle. The wads in the bottom are more supple, but are easily torn.
For fun, and out of sheer boredom, because I was on call last weekend, I threw together some light loads. What a disaster! The bases separated form the wad column in the barrel and turned this really tarry black color. They got even more brittle.
I expected them to not really work so well. I ran about five through the gun, cleaning it out after each shot. The rest i broke down.
The rest of the bag will hit the trash, but the little paper brochure that was in in the bag I'll keep. It still lists the loads with Hercules powders. Kinda cool
Don't shoot old wads though your guns.

So, don't shoot your wad if it's Pushin' Cushion'?? Got it.

Got a whole bunch of 20 ga pushin cushions that are still soft and pliable.

Storage is the key, out of the light and in a temp controlled environment and I haven’t seen a plastic wad deteriorate yet.

Got a box of WAA12 wads given to me. They were beginning to yellow. The petals would easily break off when bent backward. Into the trash

They make great packing material, a replacement for those Styrofoam peanuts.

The same happened to me only I bought them. I didn't discover it until I was 250 miles away.

Vizsla, I have a bag of OEM Winchester WAA12F114's I purchased in the early 80's at a White Elephant store for $2.69 for 250 and you would get Carpal Tunnel Syndrome before you would bend & break a petal off the wad, and the crush section of the wad is just as pliable.

I have had to throw out many hundreds of WAA12 factory wads due to brittleness, it is tough to do, but I won't risk my health or the health of my guns for the trivial savings of not discarding old OEM wads.