Here's a report by dermatologists on hair health:
Choose styling tools wisely. Knowing when to comb or brush hair is important to proper grooming. If possible, hair should only be combed when dry. The reason is that wet hair is more elastic than dry hair, which means that vigorous combing of the moist fibers can stretch hair to the point of fracture. When choosing a comb, look for one made of a flexible plastic with smooth, rounded, coarse teeth that easily slips through the hair.
Extensive hair brushing also should be avoided while hair is wet. In general, brushing the hair should be kept to a minimum in order limit breakage. "The myth that the hair should be brushed 100 strokes a day and the scalp vigorously massaged with the brush is simply untrue," said Dr. Draelos. When selecting a brush, look for bristles that are smooth, ball-tipped, coarse and bendable. Brushes used while blow drying should have widely spaced bristles to prevent increased heat along the brush, which could damage the hair.
Get a grip on using too many accessories. While hair pins and clips are popular fashion accessories, the fact is that they all break some hair since they must hold the hair tightly to stay in place. Look for hair pins with a smooth, ball-tipped surface and hair clips with spongy rubber padding where they make contact with the hair. Looser-fitting clips also minimize breakage and should be worn in different parts of the scalp so that hair breakage is not localized in one specific area.
"This problem is particularly apparent in women who wear a ponytail, and that is why I recommend that rubber bands should never used," said Dr. Draelos. "My patients who wear ponytails report that their hair is no longer growing, when in fact it is repeatedly broken at the same distance from the scalp due to the trauma caused by the tight rubber band." Rather than using rubber bands for ponytails, Dr. Draelos recommends that fabric scrunchies, which loosely hold the hair together, be used.