“No one should postpone the study of philosophy when he is young, nor should he weary of it when he becomes mature, because the search for mental health is never untimely or out of season.
To say that the time to study philosophy has not yet arrived or that it is past is like saying that the time for happiness is not yet at hand or is no longer present.
Thus both the young and the mature should pursue philosophy, the latter in order to be rejuvenated as they age by the blessings that accrue from pleasurable past experience, and the youthful in order to become mature immediately through having no fear of the future.
Hence we should make a practice of the things that make for happiness, for assuredly when we have this we have everything, and we do everything we can to get it when we don’t have it.” (Epicurus, Letter to Menoeceus, prologue)
Epicurus on why we should study philosophy