Sustainability is all the buzz.  We concern ourselves with our impact on the environment, yet rarely notice that environment's impact upon us.  We do not ordinarily strive to last very long ourselves, and by this I refer to our physical bodies.  We can find a way to recycle anything, yet we blow our entire personal energy reserves regularly.  Until we develop an attitude of internal sustainment, we should not be surprised when our Earthly vehicles begin to breakdown & betray us.  This need not be a necessary element of becoming older in years.  With great care & dedication, our bodies will serve us admirably until we choose to move on from them, no longer requiring their services.