DH owns a black tux, and a white dinner jacket, with a wide variety of cummerbunds, ties, studs, etc. Even suspenders. He updates the shirts and ties every few years, as that (along with collar styles) is what changes the most.
He also still has, and can still fit into, his Navy formal uniform.
He wears his tux a few times a year, and DS borrowed his Dad's for the Theater Dept's "Oscar" party last spring.
My father and father-in-law also owned their own, and since I had a very traditional, evening wedding, the men involved wore their own (if they had them) with only those who didn't own one renting.