Let's get one thing straight: If you haven’t washed your jeans in two weeks, there could be a colony of 10,000 bacteria per square centimeter living on the crotch. But this charming fact alone doesn’t mean you need to wash them more, at least according to the results of an informal 2011 research project at the University of Alberta in Canada. There, a student wore the same pair of jeans for 15 months. When Rachel McQueen, an assistant professor of textile science, tested the jeans for bacteria, the levels were innocuous. Two weeks after washing the jeans, the bacteria levels were essentially the same. The lesson? If you haven’t washed your jeans in two weeks, you might as well avoid the laundromat for another 14.5 months.