In 1945, the U.S. Food and Nutrition Board told people to consume eight glasses of fluid daily. Before long, most of us believed we needed eight glasses of water, in addition to what we eat and drink, every day.

The Truth: Water’s great, but you can also whet your whistle with juice, tea, milk, fruits, and vegetables—quite enough to keep you hydrated. Even coffee quenches thirst, despite its reputation as a diuretic; the caffeine makes you lose some liquid, but you’re still getting plenty.