In Your 30s: Protect
By the time you reach your thirties, your hair will have inevitably experienced some damage from your own doing and outside factors. To prevent future breakage and dryness, you should start using a protective cream.
"Sun and heat from styling are two almost unavoidable major concerns, so you want to take as many precautionary steps as possible," explains Perez. "They oxidize your strands and zap out moisture, leaving them dull and un-shiny. So a daily protective styling cream (plus a hat for beach days) will help protect hair against damage."
Try: Carita Daily Protective Cream, $35; CaritaDirect.com
Pictured: Jessica Biel