(WWJ) First, hairdressers told women they were doing too much, stripping their hair of crucial oils and washing color down the drain by sudsing up their manes every day.

Do less. Then the pendulum swung in the opposite direction and women were told to wash more often for shiny, healthy fresh-smelling hair.

Do more. But how often should you wash your hair really?

WWJ Health Reporter Dr. Deanna Lites has some expert advice.

To ‘poo or not to ‘poo? It depends on your hair texture, lifestyle and personal preferences.

“You’re not going to create a disease state by washing your hair too often or not often enough,” Farmington Hills dermatologist Wendy Sadoff said.

Some people are ditching their shampoo, called the “no-poo” movement, but there are limits. Sadoff recommends washing at least once a week.

“I wouldn’t go a lot further than that,” she said. “Your scalp does need to be cleansed approximately weekly.”

Your scalp needs to be washed, even if your hair does not, she added. It’ll become flaky and itchy otherwise.

If your scalp is itchy, wash it more often. If it’s not, try not skip shampoo for a week and see what happens, she suggests.

Washing too often could lead to dry hair. But if you’re working out, definitely do it more often, she said. To meet both those needs, as a general rule, focus shampoo on the scalp and conditioner on the hair, Sadoff said.

It’s good to know, as well, that washing more often does not cause hair loss. If it seems like you’re losing a lot of strands in the shower, it’s hair that would have come out even without a wash, Sadoff said, so don’t let that dictate your hair wash schedule.

The New York Times took on this heavy hair topic recently, and found this:

The history of hair-washing, he said, has taken many twists and turns. A hundred years ago, washing was typically a weekly experience. By the 1960s, Mr. Gordon noted, many women didn’t do their hair themselves but had it “done” and preserved. Only in recent years was washing every day thought to be the thing to do.

“I certainly did it for a long time,” he said. “Things change.”

And younger people are turning on to the anti-shampoo movement.

“The less they have to do, the better they like it, and I think they get the sustainability aspect of that,” Mr. Gordon said. “If we don’t have to wash our hair every day, then we’re wasting less water.”