We've all grown up with the recommendation to drink 8 glasses of water daily. Where's that come from?

The October issue of Consumer Reports says this conventional wisdom stems from a "misinterpretation" of a 1940s U.S. government advisory that recommended about 64 oz. (1.9 liters) of water each day. What's been overlooked all these years is that this figure included the fluid in foods and other beverages.

The modern advice is to let thirst be your guide, along with the color of your urine. A light straw shade means you're properly hydrated. Darker yellow means you're not.