As far as income goes, there are three currencies in the world; most people ignore two. The three currencies are time, income and mobility, in descending order of importance. Most people focus exclusively on income.
Tim FerrissWorld barista champions use the AeroPress to make coffee on the folding tray tables of airplanes.
Tim FerrissWhen you elevate the heels more so than you elevate the sole of the foot, you trigger a cascade of compensations in the knees and hips that cause tight hip flexors, and then those hip flexors cause lower-back pain.
Tim Ferriss