It is true that perhaps our greatest teacher is time itself, the days that we have lived and learned. It is also true that eventually time kills all of its students. We do not think about death much when we are young. As we age and get old, it creeps up on us and we can feel it looking over our shoulder. This is when the teachings of the Dao in regard to renewal and decay is important to understand. As important as it is to know how to live, it is equally important to know how to die.