I still don't know why people vary so much on this...You don't put up turkeys and pilgrims before Halloween do you? Then why would you ever put up Christmas stuff before Thanksgiving? The earliest time it's acceptable to put up and light Christmas stuff is Thanksgiving night after you've eaten your turkey. Period. It doesn't matter that Thanksgiving varies year-to-year.
As for taking stuff down, anything after President's day is a bit tacky...and truthfully even that is a bit late IMO. The only exception is tastefully done white lights because they're more winter decorations than Christmas.
Remember...No Ho Ho Ho until you Gobble Gobble the Gobbler.
At least in my world, this is how it'd be done...but we've all got our own worlds. I'll complain about people who do it differently, and welcome them to complain about how I do it....and THAT's the American way.