Grandma’s recipe has outlasted most buildings in town. Legacy can fit on an index card.

What survives is rarely the impressive thing. Something small and useful, passed hand to hand because people actually want it, can outlive institutions with budgets and nameplates. Durability comes from being repeatedly needed rather than from being large.

Ask the older people in your family to show you how they do the thing before the knowledge is only in their hands. Write it down exactly, including the parts they think are obvious. You are not being sentimental, you are copying a file that exists in one place.