[gcb0]

you completely lost me on the disposable defense.

manufacture produces much more stress than your cleaning would, causing much more to be free on the surface

[cowsandmilk]

the argument is chemical degradation with age, not physical abrasion. You leave plastic out in the sun and reactions occur that can depolymerize the plastic, releasing monomeric components. In the case of polycarbonate, those components include bisphenol.