I have heard it said that most people take better care of their vehicles than they do their bodies.
In the yogic philosophy the body is the vehicle for the soul. This body that you have been given for this lifetime is your ride through this life.
Asana is our way into the physical body for that scheduled maintenance. Yogic postures are a way to keep the joints lubricated for mobility and maintain a foundation of strength that carries us through all the stages of life. We learn how to focus and quiet our minds.