I‘ve written before about the weird and myriad processes which affect Retro Rubber. The specific formulation - including colour fillers - heavily determine how well RR stands up, with models from the same manufacturer differently prone to cracking, splitting, going papery, etc. While storage conditions are vital, formulation is equally important. IRC FRO folding seem remarkably robust and long lived. But for certain there are three things certain in life: death, taxes and the decay of retro rubber. It just goes on getting old, with no remedy. And for sure this affects prices - in Lockdown, prices were creeping up towards new rubber, Now, they are leaping ahead in more and more cases (White Porc Lunacy is such an outlier that we can safely ignore it).