Look at how mindful we are of our smartphones. People have little recharging shrines all over their houses, with a cord permanently attached to an outlet right by the door or by the bed. For many of us the first thing we do when we get home is make sure our phone gets recharged. (My editor on this book keeps a cord at the office to recharge his phone in case he forgets, and another in his knapsack that he carries with him.) We’re all exquisitely aware of the recharging routine of our phones: how often we need to do it; how long it takes; how long we can go without recharging it; where the nearest outlet is. And yet, on the flipside, with our bodies and our minds and our souls, we’ll run them right into the ground until they shut down. You know the warning that comes up on your phone when it’s running out of battery power: “Alert! You’re running below 20 percent!” Unfortunately, we don’t have an indicator like this that alerts us when our bodies are out of energy. Imagine being in a meeting with someone and suddenly realizing, “Oh, wait, we need to stop here; I’m only at 10 percent—I need to recharge.”

– Thrive: The Third Metric to Redefining Success and Creating a Life of Well-Being, Wisdom, and Wonder by Arianna Huffington