There is a fountain of youth: it is your mind, your talents, the creativity you bring to your life and the lives of people you love. When you learn to tap this source, you will truly have defeated age.
Ability is not something to be saved, like money, in the hope that you can draw interest on it. The interest comes from the spending. Unused ability, like unused muscles, will atrophy.
Here I may perhaps mention that only because men are in fact unequal can we treat them equally. If all men were completely equal in their gifts and inclinations, we should have to treat them differently in order to achieve any sort of social organization. Fortunately, they are not equal; and it is only owing to this that the differentiation of functions need not be determined by the arbitrary decision of some organizing will but that, after creating formal equality of the rules applying in the same manner to all, we can leave each individual to find his own level.