Utility is an impermanent thing: it changes according to circumstances. So with the disappearance of the ground for friendship, the friendship also breaks up, because that was what kept it alive. Friendships of this kind seem to occur most frequently between the elderly… and those in middle or early life who are pursuing their own advantage. Such persons do not spend much time together, because they sometimes do not even like one another, and therefore feel no need of such an association unless they are mutually useful. For they take pleasure in each other's company only in so far as they have hopes of advantage from it. Friendships with foreigners are generally included in this class.

And in addition they need time and intimacy; for as the saying goes, you cannot get to know each other until you have eaten the proverbial quantity of salt together. Nor can one man accept another, or the two become friends, until each has proved to the other that he is worthy of love, and so won his trust. Those who are quick to make friendly advances to each other have the desire to be friends, but they are not unless they are worthy of love and know it.