Hygiene still counts, of course -- washing up helps prevent colds, for example. So teach your kids to wash their hands before eating and after using the bathroom or playing outside. Just don't overdo the rub-a-dub: For newborns, a daily sponge bath is a good idea. Babies 3 to 6 months can be bathed daily as well, because of their messy diapers. But older kids may need a bath only every other day, depending on how dirty they get. On other days, you can wash just their face, hands, and feet if they're grimy.
Everyone loves a clean baby, but apparently there's such a thing as too clean: Kids from birth to age 3 who are bathed or washed more than twice a day are more likely to develop asthma or severe eczema, British researchers have found. "Exposure to a little grime may protect kids," says Michael Welch, M.D., chair of the American Academy of Pediatrics's section on allergy and immunology. "Because their immune systems are still maturing, they seem to benefit from being around viruses, bacteria, and dirt."