when do the elves leave

The elves work tirelessly all year long, but they only have a short time to prepare for Christmas. The workshop is a busy place in the weeks leading up to December 25th. Toys need to be designed and built, the sleigh needs to be repaired and tested, and Santa needs to make his annual visit to the North Pole to oversee everything. The elves generally stop working around midnight on December 24th, just in time to prepare for Santa's visit and prepare their own homes for the holiday.