“The struggle requires the following: First, one should provide his body with whatever it needs – sleep, food, and so on. Then, he should aim at cutting off his spiritual passions, such as his desires, his egoism, his envy and so forth. And afterwards, he should exercise more abstinence in food and sleep. That is when bodily asceticism has meaning. One must observe himself carefully and try things out. Through trial and error, he will find his own limits. Even the inexperienced grocer will inadvertently tip the scale, either by putting on too much or too little. But later on, when he has acquired experience, he will put just the right amount on the scale. In any case, when a person is younger, he can practice more asceticism. As one ages, his physical strengths give way and he can’t overly exert himself. If he pushes himself too hard, he can even cause harm to his health. This is why, one ought to re-evaluate his strengths from time to time and adjust himself to his new condition.”

– ‘Passions and Virtues’