What is the EVOLUTIONARY advantage of death?

The explanations that I read is that aging is just that the rejuvenation/repair mechanisms aren't perfectly efficient and so the "wear" builds up, causing aging. If, because of disease (caused by parasites) and predators, most of the individuals in a certain population are dead by 45 years old, there is no evolutionary advantage to develope repair mechanisms that will keep a body in perfect health past 45.