[Prudence] is the virtue of that part of the intellect [the calculative] to which it belongs; and . . . our choice of actions will not be right without Prudence any more than without Moral Virtue, since, while Moral Virtue enables us to achieve the end, Prudence makes us adopt the right means to the end.
I'm not advocating the strenuous life for everyone or trying to say it's the choice form of life. Anyone who's had the luck or misfortune to be an athlete has to keep his body in shape. The body and mind are closely coordinated. Fattening of the body can lead to fattening of the mind. I would be tempted to say that it can lead to fattening of the soul, but I don't know anything about the soul.
True understanding is possible only when we are fully conscious of our thought, not as an operative observer on this thought, but completely and without the intervention of a choice.
I have a few minor rules for myself but I break them all the time. For example, when translating from Romance languages to English, there is often a choice between a Latinate cognate and a Germanic equivalent. An easy example would be the Portuguese escuridão: English offers both obscurity and dark or darkness, and some translators will tell you the Latinate word is generally reserved for poetic and figurative expressions, while the Germanic word is used for colloquial and idiomatic use.
There are the terrible ones who carry about in themselves the beast of prey, and have no choice except lusts or self-laceration. And even their lusts are self-laceration.