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1. You pull your hair too tightly into a bun, pony or braids every day.
Repeatedly pulling hair tightly stresses follicles and can hinder healthy growth, which may lead to breakage at the temple and hairline, thinning, and even hair loss, says trichologist Elizabeth Cunnane Phillips. Switch up your style or keep your pony loose and secure it with a seamless fabric hair tie—elastics with metal can cause breakage.

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2. You welcome summer by lightening your haircolor.
Bleaching agents weaken hair, making it more susceptible to damage, says Mark Debolt, colorist at the Marie Robinson Salon in NYC. Post-coloring, make a hair mask your BFF: If you’re a brunette with highlights, look for a color-protective mask to prevent brassiness; a protein-rich mask is best for blondes. And apply a UV-protectant spray before going outside.

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3. You constantly flatiron or curl your hair to fight frizz.
Heat styling depletes hair of moisture, causing dullness and breakage, says Phillips. If you simply must use hot tools, try a hydrating shampoo and conditioner and a strengthening hair mask weekly; before styling, apply a heat-protectant spray. And though you may be able to heat your tool up to 450 degrees, dial it back to about half that.