CLEAN SLATE VS MAINTENANCE. “The strategy that multicellular organisms such as humans use to project themselves into the future is to create new cell colonies from a single undifferentiated cell rather than maintaining existing colonies indefinitely. The main reason is that reproduction is more flexible and robust than maintenance, and it provides a way of starting over with a “clean slate” and slightly different genes.”
https://www.quora.com/Death-and-Dying-According-to-the-theory-of-evolution-why-do-we-die