We have a tradition of doing it Christmas Eve night if I am not working in the evening. We like to do it as a family and DP sometimes doesn't finish work until 3pm and I start work at 5pm. If I am working we do it the Sat/Sun before Christmas so the earliest would be the 18th. I don't really get into the Christmas spirit until the children have broken up from school. I think it all gets a bit boring and takes the excitement out of if if you start with all the Christmas festivities too early on. In RL I seem to be in the minority with this view though.