Nothing frees us from swinging between hope and fear better than setting limits on our success. Don't let Fortune decide when to stop your career. Stop on your own, long before you think you need to. This way, your ambitions will still motivate you. But they'll stay within reasonable bounds. They won't push you into huge, unclear ventures that could ruin you.
Yet nothing sets us free from these alternations of hope and fear so well as always fixing some limit to our successes, and not allowing Fortune to choose when to stop our career, but to halt of our own accord long before we apparently need do so. By acting thus certain desires will rouse up our spirits, and yet being confined within bounds, will not lead us to embark on vast and vague enterprises.