Who wears them
Who a style is usually worn by, as the sources describe it. Anyone can wear any style.
Mostly women
Many hairstyles have been worn mostly by women, often because of rules and customs about how long women's hair should be, how it should be dressed and when it should be covered. Long hair was expected of women in most cultures for most of history, so women's styles include the great updos, braids and set styles, while short cuts for women, such as the bob, became a statement of independence.
Mostly men
Men's hairstyles have often been shaped by rules: of armies, schools, faiths and governments. For much of the 20th century in the West, men wore short, tidy cuts made at the barber's, from the crew cut to the side-parted regular haircut
Anyone
Many hairstyles are worn across genders. Locs, afros, buzz cuts, ponytails, mullets and undercuts are worn by people of any gender, and many styles that began with one group have spread to everyone
Children
Children's hair carries a surprising amount of ritual. In many cultures a baby's or child's first haircut is a ceremony: the Hindu mundan, the Jewish upsherin at three, the Muslim shaving of a baby's head on the seventh day, the shaving of a baby's head at one month in some Chinese families
Brides and weddings
Brides in almost every culture wear their hair specially dressed, and wedding hair often says that a woman is leaving girlhood. South Asian brides wear buns and plaits wreathed in jasmine and jewels; Japanese brides a traditional shimada under a white hood; Nigerian brides a towering gele; European brides a veil over an updo
Faith and religious orders
Hair has a place in almost every faith. Some ask believers to keep it uncut, like Sikh kesh and the locks of the Rastafari; some to shave it, like Buddhist monks and nuns and Hindus making offerings; some to leave a part, like the Jewish payot and the Hindu shikha; and some to cover it, as many Muslim, Jewish and Christian women do
Uniform and work
Armies, navies and many workplaces set rules for hair, for hygiene, safety, helmets and a uniform look. The induction cut given to recruits, the high and tight of the United States Marines, and the crew cut all come from military life
Subcultures and music
Subcultures and music scenes have produced some of the boldest hairstyles of the past century. Teddy boys wore greased quiffs and ducktails, mods neat short cuts, skinheads close crops, punks mohicans and liberty spikes, goths teased black hair, and hip hop the hi-top fade