In November, I tend to watch films associated with Christmas, like Die Hard, Trading Places and Gremlins. Obviously there are many more films with Christmas associated with them and they'll have things like Dan Ackroyd dressed as Santa Claus or the film is set at Christmas time but it's not about Christmas itself. Those kind of films are fine. They're films you could probably watch at any time of year but I associate them with Christmas - due to there being Easter eggs within them for Christmas - so this is why I start watching them in November.
In December, all the other more typical Christmas films are constantly allowed. Some of my favourites: A Muppet's Christmas Carol, Santa Clause films and Elf - I allow them in November but not back-to-back because I don't want to kill them before Christmas. I love watching Love Actually and The Holiday but this rule stops me from - like I said - killing the films and annoying my house mates from the same films over and over and over.
I rewatch films like no one else, so at Christmas I want to make sure I save time for them. Those around me think I'm crazy but I just want to make sure I get my Christmas fix.