I grew up celebrating the full 12 days of Christmas, until Jan 6th, which is also when I was born, and the official start of Carnival, or Mardi Gras Season, until Ash Wednesday kicks us into Lent.
So- we leave everything up for Christmas, Tree, cards, lights.. until January 6th, then the new "season" begins and Mardi Gras decor is appropriate and applied.
We also do not buy cut trees. Usually we buy a live tree, mostly citrus and decorate it and then plant it or place it in a raised container when the time comes. This year, we bought a Camellia to replace one of the ones that we lost last year. It's like the seafoams, only soft pink on each petals edge, and it name is "October Affair" (VERY DRAMATIC NAME for a sweet little bloom! )