The mechanism is specifically: a muscle (stapedius) attached to one of the bones of the inner ear (stapes) pulls it away, effectively breaking the sound conduction pathway.
This mechanism does not wear out. It can, however, be disrupted by damage to the muscle in question, or to the nerve innervating that muscle, or the portion of brain controlling that nerve.
However, you can still conduct sound without the stapes in place. It’s less effective - that’s why the bones of the inner ear are there at all - but in loud settings, and certainly in conditions where you can conduct sound effectively to the bones of the skull (eg, headphones), you can still pass enough sound to the cochlea to damage your hair cells.