When it was just me and the wife the tree and decorations went up as close to the 25th as was possible, thats if they went up at all.
Now we have kids, the wife insists the decorations go up on the 12th to get our little boys birthday out of the way.
Must admit that as my son gets older i look forward to christmas more and more, it means i get to play with Lego, scalextric sets etc without feeling guilty.