Christmas doesn't end until Candlemas on February 2.
However, our family celebrates Three Kings Day. On 12th Night, we have a party with the kids, a great feast, and we exchange gifts in honor of the Magi. It is on this night, I bake a Three Kings Cake which we have each week until Mardi Gras!
We start packing away our decorations after Epiphany which usually takes about a week or two. We leave our lights out until the end of January.