Aging is a complex dynamical process. We all have skin in this game, since at the end of it we die. What are the simple, but not too simple, mathematical models we can use to learn aging dynamics from “big” health data? I will present two dynamical models of aging to simplify and understand the aging process. The first is a model of declining functional health. The second is a model of biomarker homeostasis. I will tell you about cool behaviors the models exhibit, the open questions we see, and how we are addressing them.