From my previous experience: Change Freeze starts the weekend before Thanksgiving Holiday due to a significant increase in spending that week and the weeks thereafter, and it continues until a weekend in January (such as 8th or 9th).

During this same time period a lot of employees take personal time off, so if a Change fails the right SMEs might not be available to restore service quickly, this is another reason for why it is not lifted after Black Friday.

Do you do business in China? Then maybe another Change freeze during the Lunar New Year week.

Bringing online a new Data Center? Change Freeze. You want your resources available in case those initiatives need them, and not busy with some other apps that failed.

Are you gonna miss your Availability target of 99.9999 for the Quarter, implement the Change Freeze to get your number back up 😄

All of these require the use of the NOW platform in one way or another, and imagine what would happen if someone broke the paging service at this time, so most apply the same freeze to the NOW platform.

The good news is, this should not impact your dev activities due to multiple environments and updatesets. But many customers take this opportunity to run their upgrades in lower environments so they are ready for January Prod release.