Personally, if I were programming a music station, I wouldn't even think of programming any Christmas music prior to December 1st.
From December 1st through 10th, I'd program one Christmas song every third hour.
From December 11th through 17th, I'd program one Christmas song every other hour.
From December 18thg through 12 Noon on December 24th, I'd program one Christmas song every hour.
Only from 12 Noon Christmas Eve through 12 Midnight on Christmas Day, would I go all-Christmas.
The idea is that I'd ease my listeners into the season without "hitting them with a 2-by-4". And going 24/7 Christmas at the beginning of November one way to hit a listener with a 2-by-4.