The truth: hot tools are a major investment. A top-of-the-line blowdryer will keep your strands from frying and give you glossy shine, but it will cost you! So why would you ruin your trusty tool by tangling the cords and clogging the vents? T3 celebrity hairstylist David Lopez has a strict maintenance regimen, so his tools are at peak performance for clients like Chrissy Teigen. He told SELF some of the most common flatiron and blowdryer sins women are making that will eventually send your tools up in smoke.