“Commonly old age brings on retirement from work; but in many cases it is truer to say that retirement brings on old age. The mind, like any other organ, retains and renews its strength only through exercise. In active life, whatever its negative stresses and trials, this exercise is emotional as well as rational, creative as well as defensive. The demands of communal effort constitute an irreplaceable exercise of mind, as does the state of being responsible or the state of being needed, no matter what the responsibility or the need. In retirement we lose these healthy activities, and the freedom we gain is often a poor exchange for the enervating vacuum of challenge, the dry rot of immobility which leaves us, month by month, less supple, less responsive and less vigorous. And even worse than this, to the extent that in active life we have established our own identity as social beings, we. become in retirement less and less ourselves.”

Robert Grudin, Time And The Art Of Living (Page 117)