How often have you been vacuuming and then turned off the vacuum only to see stray hairs—your own or your pet’s—still on your carpet? No matter how hard and often you vacuum, they’re still there. Now imagine all of the hairs you cannot see because they’ve worked their way below the surface. Experts tell us that one human sheds an average of 50 to 150 hairs a day. Dogs, depending on the breed, shed many times that amount, as do cats. The mess of pet hair can be enough to drive pet owners nuts. I met my first Shark vacuum in July 2012. That experience rocked my world. I was both amazed by the piles of debris, dirt, dust, and who knows what else that thing sucked out of the carpet, and plenty embarrassed. It’s not like I never cleaned house. In the seven years since then, I’ve written about …