Unfortunately I have not made good experiences storing shoes from materials like crocs.
As far as I know crocs are made from croslite which is a type of EVA foam, which is a similar to the material shoe soles or flip flops are made of.
From my experience, this material is ageing worse when not regularly in use. It might sound counterintuitive, but the longer you store your shoes the more brittle the material becomes (even if you shield it from extreme temperatures and direct sunlight).
I think this effect is most known to occasional hikers who find their soles falling off or crumbling apart on the first few miles after they stored their boots for a couple of months/years.
So regularly wearing your crocs for a few hours a month might increase their longevity. Although I don't know if crocs has added something to their patented EVA foam to prevent this from happening.
Hope this helps and good luck as well :)