Photo by Ron Galella, Ltd./Ron Galella Collection via Getty Images. Your hair’s texture changes every seven years or so—but not entirely because of damage brought on by heated styling tools and monthly appointments with your colorist. Hormonal changes—using birth control, getting pregnant, and even simply aging—tends to weaken the hair as well. Think for a second: how many flyaway hairs did you have at 19 years old versus 28 years old? Or 38 years old, for that matter?