As it applies to timeshares, the term "Anniversary Date" can have multiple meanings. In traditional timeshare programs, the "Anniversary Date" marks the starting point of the usage period. Some resorts define a "use year," within which owners must use their timeshare or risk losing their week for that calender year. In this instance, the Anniversary Date is often defined by the date in which the original purchaser bought the timeshare from the resort developer. When you are dealing with a resale timeshare, the Anniversary Date generally remains static from seller to buyer.
When a timeshare resort offers a points program, the term "Anniversary Date" refers to the day on which earned points accumulate. Every year on this date, your points will be refreshed. Many programs allow owners to bank, or accrue their points, and in this case, this date marks the day that additional points will be added to the existing ones. It is important to know your Anniversary Date so that, if you're planning ahead for your vacation, and/or relying on banked points, you will be aware of your current points budget.