In so many different ways, this message comes across in the Holy Word. It's an ongoing, unending thought. It's tied to the thought of Newman: "To live is to change, to change often is to have become perfect."
The renovating power is the Spirit and the fount, for it is Christ Jesus. He is the source from whom all good flows. We are to be putting on always that which is good, that which is better. No matter how old we are, Jesus opens to us challenge and promise of newness. "Your attitude," Pauls writes tothe Philippians, "should be the same as that of Christ Jesus" (Phillippians 2:5, New International Version).
Another way to think about it is to see that we're all called to a mind transplant, and that Mind is infinite, without end, and so the change is constant, and the change is ever calling us.