When do you put your Christmas tree up?

When our children were little we couldn't afford a Christmas tree. If we had a tree we would not have a turkey. I came up with a work around. One of our daughters has a little doll cradle. The other had a doll. I cut a piece of cardboard into a 4 pointed star, wrapped it in tinfoil and hung it from the ceiling on a long piece of thread. We filled the cradle with gold coloured tinsel that we had used to decorate our Christmas trees in the past and put the doll, wrapped in old rags into the cradle. The kids each put one of their stuffed animals around the cradle thus creating a creche. To this day the first thing the kids and grandkids do is put up the creche. The number of animals has increased but the same cradle and the same doll and the same star get put up faithfully. Sometimes we put up a tree and other times we don't bother but that creche MUST be put up at least a week before Christmas.