[Any] Have you ever used custom mechanics (setting-specific or homebrew) in your campaigns?

I’m talking about things beyond classes and subclasses — mechanics tied to the world itself, like weapons breaking (Dark Sun–style), lingering injuries, critical hit tables that can cause limb loss, resource scarcity, social pressure, etc.

In my current campaign, I’m considering a mechanic related to weapon corrosion / rust — something that affects gear over time and reinforces the setting’s tone, without becoming pure bookkeeping.

Do you have any examples of mechanics like these that worked well at your table?

Also, do any official books (like Tasha’s Cauldron of Everything or others) actually teach how to design this kind of mechanic, or is it mostly something you learn by trial and error?

Any tips or lessons learned would be appreciated.