Cast iron skillets

Metal roof

Composite deck

That may be it, I will probably outlive my other possessions.

Runners-up:

We are still using a Dyson vacuum that my uncle gave me, used, when he got a new one, at least 15 years ago. Longer I think, and don't know how long he used it before that. And just replaced my KitchenAid mixer with a bigger one and gave my old one to one of my kids, that was 25 years old and is still going strong.