Christmas cards should be mailed out as soon as possible, ideally a few weeks before Christmas so that they arrive in time for the holiday season. This allows friends and family to enjoy the greetings and messages of goodwill and holiday cheer. If you're mailing them from a different country or have a longer distance to travel, it's a good idea to allow more time for delivery. Remember to include the recipient's full address and correct postage to ensure they arrive safely and on time.