Tradition is anything your grandparents did that you also do. Few people remember their great-grandparents well enough to know if they also did something, (with modern medicine this is somewhat more likely, but still not common) and thus few have any clue if it is something their grandparents started or not.

Unless of course it was written down. Some religions have things written down as of a few thousand years ago. Just looking at them though we can see plenty of examples of things written down being ignored for a while and then some reformer comes and revives the tradition. Anything not written down is questionable in ability to survive for long.