Let’s start with the ending: you don’t need to wash your jeans. Unless there are spots or stains you want to remove or they’ve just gotten terribly dirty, with normal wear jeans don’t need washing, according to Tech Insider.
Given the wide selection of jeans, including colors, distressing, various washes, fits, and styles, your best bet is to buy jeans that fit and look exactly as you would like them. There’s no need to roll them in mud, pound them with rocks, soak them in salt water, or run over them multiple times with your car to break them in. Jeans today come in so many varieties you might as well just buy the look and fit you want — and then never wash them.
Levi’s says jeans don’t need to be washed. Hot-water washing fades jeans and tumble-drying wears them out. Even worse, washing jeans wastes water and energy.
Jeans can take on an odor after a while that can offer a good reason to wash them, but if you’re concerned about health hazards due to bacteria build-up, scientists say you needn’t worry. According to Bernhard Redl, associate professor in molecular biology at the University of Innsbruck in Austria, there is no evidence that jeans worn as everyday clothing are a health hazard if they’re not washed.
Rachel McQueen is a professor of human ecology at the University of Alberta in Canada who focuses on textile odor development and retention. Unless you work or are going to be in an environment where sterile clothing matters, such as a hospital, for example, “sanitizing your hands is going to be a more important issue here than washing your jeans,” McQueen said.
One of McQueen’s students wore the same pair of jeans for 15 months without washing them. They measured bacteria at various times and found the bacteria count was about the same after 15 months as it had been after 13 days. What they found was normal bacteria and cells from human skin.
And forget about freezing your jeans to kill odor. “It is clear that freezing does not kill most of the bacteria,” said Redl, “but puts them in a dormant state.” McQueen said, “I think airing your jeans outdoors in the sunlight would be a more effective method of getting rid of odors and a lot of bacteria.”
So don’t wash your jeans — unless, you know, you feel like it.