While everyone’s beauty routine is unique, there are still some basic guidelines if you’re looking to prevent damage to hair, skin, and nails. Now, some of these “rules” are tried and true, like prepping your hair with a heat protectant spray before blow drying or styling with a straightener (bonus points if it’s blended with ingredients like nourishing coconut and argan oil). But some beauty mistakes are less obvious. For example, if you’re bathing without a shower filter, there’s a good chance you’re exposing your skin and hair to chlorine and hard water minerals. This can lead to itchy, irritated skin as well as hair that’s dry, damaged, and frizzy.…