Personally I feel that Christmas songs (and other Christmas themed things) shouldn't start sooner than December.
Personally I feel they shouldn't be on at all, or at most on as often as you would reasonably expect from a random selection.
Christmas songs are, for the most part, Baby Boomer nostalgia. I can take solace in the fact that, a few decades from now, they'll be forgotten relics that finally don't get the nonstop playtime they've enjoyed since the 1950s.