There’s plenty of advice—and at least one scientific study—floating around out there about how often we should wash our jeans. But according to a recent video from the folks at HowStuffWorks, deciding when (and how) to clean denim mostly boils down to personal preference.

In it, Ben Bowlin explains that washing jeans has a real impact on the look and feel of the material. While some clothing dyes soak into fabric, indigo—which is the dye used to give jeans their deep blue color—does not. Instead, it sits atop the threads, and eventually begins to chip away, causing the color on jeans to fade. Washing them immediately after purchase can cause a more uniform fade, as the washing machine evenly removes the dye, while wearing them for a few months beforehand will lead to an uneven change in color, which will vary from person to person. According to Bowlin, these fade patterns are so unique to the wearer, they’ve even been analyzed by the FBI while tracking criminals. Anyone trying to develop a unique fade pattern and preserve the texture of the raw denim, says Bowlin, should wait awhile before washing their 501s. 

Of course, there are other factors to consider when deciding when to toss your favorite pair in the spin cycle. Washing jeans can soften stiff denim, making it more comfortable. And, of course, washing gets rid of bacteria. While it’s totally safe to hold off on washing your jeans, they are still picking up dirt and germs when you wear them. Ultimately, Bowlin argues, there are three main factors you should think about before you wash your jeans: How you want them to look; how you want them to feel; and how comfortable you are wearing jeans that might be just a little bit dirty. Check out the video above to learn more about washing strategies and the science of denim fade patterns.

[h/t Lifehacker]

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