I did not know that yesterday!

While it's true hair is sometimes shinier after a hot oil treatment or a beer rinse, the switching shampoos theory seems to be a tangle of marketing hype. Because unless the suds are prescription or for dandruff, most shampoos have the same active ingredients.

Regardless, some believe an occasional clarifying shampoo can get rid of " product buildup." Where do people get this idea? From some stylists and some product lines. I need more proof.

According to Cosmetic Mall's Beauty Tips , frequent use isn't the only reason to purchase a rotating cast of shampoos. The weather is also a culprit. "In dry winter air, a moisturizing shampoo may become necessary. In the summer, you may need a volume-building shampoo which will help keep your hair fuller."

But before you spend your paycheck on shampoos for all seasons, famed colorist Robert Craig has another theory: it's the water. After learning detergent manufacturers alter their product based upon each region's water hardness, he developed shampoos to do the same. He says, "if you are using a shampoo formulated for the water it is used with...there is never a need to change products." Maybe only a different kind of marketing hype, but it's an argument I'd buy.