The amount of time that Christmas cookies will last depends on a few factors. First, it depends on the type of cookie and the ingredients used. Some cookies, such as sugar cookies, may last up to a few weeks if stored properly in an airtight container. Others, such as shortbread cookies, may only last a few days. It also depends on how they are stored. If they are stored in a cool, dry place and wrapped tightly, they should last longer than if they are left out on the counter.