“The brow area is especially important because brows are the highest point of the face that shield the eyes,” says celebrity brow artist René de la Garza (Think about it: Makeup artists recommend tapping a highlighter on the brow bone, as that’s where the sun would naturally hit). “Excessive amounts of sun exposure can make brow hairs dry and brittle,” and that crispiness can lead to sparser patches over time, altering your brow shape. Not to mention, they can fade in color—as someone with naturally light brows, I can attest they all but disappear in the summer, which is why I up my brow tinting schedule during the summer months.