One problem I have with all-Christmas formats is that while one could assemble a Christmas music library of over 3,000 selections, those 3,000 selections might only encompass about 60 to 70 different songs!
That's why, if I programmed a music station, I wouldn't even start airing Christmas music until December 1st, then gradually ease listeners into the season (one Christmas song every three hours from December 1st-10th; then one every other hours from December 11th-17th; then one an hour from December 17th until 12 Noon on Christmas Eve) before going all-Christmas for just 36 hours (12 Noon Christmas Eve until, 12 Midnight Christmas Day).
Perhaps songwriters should come up with new Christmas songs so that those listening to all-Christmas radio don't end up hearing "Let It Snow! Let It Snow! Let It Snow!" every hour on the hour.