Lots of lather means a shampoo is cleaning well.

Not true: Surfactants, the ingredients responsible for bubbly foam, are added specifically to satisfy lather lovers, not to deliver better results.

Always rinse with cold water.

Not true. Although it can help conditioner cling to hair better (which may yield shinier results), cold-water rinsing won't do much of anything after a shampoo, says David Cannell, corporate vice president of technology for the hair-care company Redken.

Focus washing only on your roots.

True, especially for those with dry hair. Rinsing will carry the suds through to your ends, which is all the cleaning they need, says Angelo Denofrio of the Aspect Beauty Salon, in Los Angeles.

How often should you wash your hair?

Unless you have oily hair, stylists generally recommend shampooing only every other day or so, to allow natural scalp oils to coat the hair shafts and boost shine; those with kinky or relaxed hair should shampoo only once a week. On days when you skip the suds, you can still condition and rinse for a tangle-free comb-out, says Miami hairstylist Ric Pipino.

Do you need actual shampoo?

When Real Simple staffers asked friends and family what they use to wash their hair, they were amazed to find that some use dishwashing liquid, bars of soap, and even dog shampoo. However, experts say it's best to stick with shampoo, which balances cleansers to remove dirt and oil with conditioners — unless, that is, you want to strip your color. Dishwashing liquid is the secret to removing hair color, says Warwick Grange of the Sally Hershberger Salon, in New York City.

Tips

Brushing with a boar-bristle hairbrush before getting in the shower will help to loosen the clumpy scalp flakes that are common with oily hair.

If you have curls, avoid crushing them while shampooing. Rough treatment disrupts the curl pattern and can lead to puffiness or frizz.

Always be sure to rinse completely. "If you apply conditioner over suds, it locks them in and hair looks dull," says Beverly Hills stylist Stuart Gavert.