Calendars are not items that you necessarily think of as highly collectible. They are year specific for sure, and often people mark on them. An exception would be a perpetual calendar that can be used from year to year.
Still, wouldn't it be fun to check out a calendar from a year significant to you Disney did and continues to make calendars featuring some of its most beloved characters. Those calendars, however, often get pitched in the trash at the end of the year to make way for the new calendar…and the new year!