What parts are breaking down on yours? The earpads are of course replaceable, and if you had the awful loose yoke problem I’m guessing you wouldn’t be so calm.

Cushions (yeah replacable but not super cheap), the cable that connects one earpiece to other, the bit connecting the earpieces, the hinges around the earpieces.

Literally everything. The sound is still great and battery is awesome. But I doubt it will last long.

(Just to be clear: I've used it A LOT over the years, and is already worth every penny I spent on it)

Huh. For what it’s worth, the Chinese lambskin (not generic “leather”!) pads that you can get for ~$15 from Aliexpress, Geekria, etc. work as well as the official ones in my experience. (For other headphones, you can’t always get generic replacement pads made of the same materials.) The only difference I’ve been able to discern is the L/R labels are printed using a different technique.

Let me have a look. Do you think the material is of good quality and healthy (no weird questionable materials for wearing/skin contact for long time with sweat etc)?

I’ve spent a few weeks with mine and, as best as I can tell, they’re indistinguishable from the original ones, except the dye of the L/R markings is on top of the cloth rather than inside it. These ones (black lambskin, currently 14 USD): https://www.aliexpress.com/item/1005005961714330.html.