As a matter of fairness many Seller/Developers and clubs will create a floating usage model that corresponds with holidays so that members are assured occupancy during the holidays at least every few years, depending on share size, inventory, and owner usage patterns.  This may allow for some predictability depending on the model used for scheduling years in advance.  For example if the rotating/floating calendar has a fixed component, where each owner would automatically move through the calendar each year by a few weeks, one could determine years in advance when they would have holiday at their vacation fractional ownership home.