I regularly use tubes from the 1920s... globe 10s, WE301A rectifiers, vintage 845s from the 20s, 30s, 40s. Probably the earliest is late 1920s for some Globe 10s, though some of the globe 866s date from around then too. All working great, used daily, doing what they were designed to do, 80+ years later. Gotta love it.
-Ed
-Ed