What is the appeal to tradition fallacy?

Assuming something is right or better simply because it's old, traditional, or "the way it's always been done."

The pattern: X is old/traditional, therefore X is correct. It fails because age alone doesn't make a practice correct — people have persisted in false beliefs for centuries (witches causing disease long predated germ theory, yet was wrong).

"We've always promoted by seniority, so it must be the best way to choose managers."

Longevity shows a practice survived, not that it's good — it may have survived through habit or inertia. The mirror image is the appeal to novelty ("it's new, therefore better"), which is equally fallacious: newness alone doesn't confer quality either.

Tip: "Stood the test of time" is only meaningful if the thing actually passed tests over time (like a well-tested scientific theory) — mere persistence isn't a test.