I am also curious about what brand these components are. I see no reason not to list it. Maybe just an outlier, or maybe there's a pattern, so that info would be helpful.
I've got components older than my adult children which are still going strong. Things with moving parts will sometimes need maintenance like speaker surrounds or CD belts. I consider those more like brake pads or tires on a car which aren't a surprise, they wear with use and age. Anything else would just be the occasional capacitor failure, CD laser, or other simple things, which I consider more like a water pump or timing belt that also has a shelf life.

