Ticket due date is a threshold to indicate that ticket has to be closed by a certain date. It can be adjusted manually, by rules or inherited from the current SLA configuration. Tickets in a folder can be sorted by the due date field allowing it to serve as a priority, in which tickets are to be handled. If used like that it allows to solve the problem when tickets with recent activity always float on top of the list obscuring tickets with no recent updates to them.
In conjunction with consolidated ticketboxes ticket due date allows to monitor and maintain ticket priority across several ticketboxes without any priority conflicts.