When the hour of dire need draws nigh Keep the faculty of effort alive in you by a little gratuitous exercise every day. That is, be systematically ascetic or heroic in little unnecessary points, do every day or two something for no other reason than that you would rather not do it, so that when the hour of dire need draws nigh, it may find you not unnerved. William James, Principles of Psychology wisdomneed
Economy of material and labor Whatever the comparative merits of [various bed framing methods], what is clear from Aristotle's Mechanica is that economy of material, and labor, was as much an issue in ancient times as it is now. Henry Petroski, The Evolution of Useful Things The requirements of economyThe art of not constructing simplicity