What’s in your bed? According to a new study, the answer is pretty gross. One of the biggest problems? We don't clean our bedding enough. The study found that 45% of single men only wash their bedding once every four months. Single women were much better -- cleaning their bedding around every two weeks. Couples washed their bedding around once a month. Consider this: In just four weeks, a pillowcase was found to have 39 times as much bacteria as a pet bowl, while sheets have 5.4 times more bacteria than a toothbrush holder. And if you wear socks to bed, stop! They have the same bacteria carried by cockroaches.