An easy action that takes just 20 seconds can cut your risk for catching a cold, flu or other contagious diseases by up to 51 percent, recent studies show. And if everyone made it a regular habit, one million deaths a year would be prevented, according to the Centers for Disease Control, which calls this habit the single most important way to avoid spreading infection.

Frequent hand washing with soap and water can save you money—and misery—by helping you avoid medical bills, missed workdays, or having to stay home with a sick child. And you’ll also protect your friends and family: A CDC survey found that 40 million Americans a year fall prey to illnesses spread by hands, which can harbor up to 500,000 bacteria per square centimeter.