What Makes A Tradition?

This time of year in the U.S. is filled with traditions, from a big turkey meal to trimming the tree to making resolutions. These traditions can be small and extremely personal, or common and prevalent throughout the culture. Some are rooted in religious beliefs, some are centered around family, and some are just for fun.

But there is a larger question at work here: does a tradition have to be an annual event? Is it necessarily centered around a holiday? What is the difference between a tradition and a routine?

What makes a tradition?

Related questions: How do you make a tradition? What does it mean to be thankful? Where do shared ideas exist? How are patterns important?