Jeans are shockingly resilient clothes that may not need to be washed as often as you think. With all the contradictory information out there, this video helps explain why you might not want to wash your jeans. As this video from HowStuffWorks explains, the indigo dye in jeans is the source of all the controversy about whether to wash. Washing raw jeans too early can cause the indigo dye, which gives jeans their distinctive colour, to fade too early. Some companies even advise buyers not to wash their jeans for six months if they want unique fade patterns, as opposed to the single uniform fade that you get from a machine wash.
The video also deals with the obvious question of cleanliness. Most of the bacteria that can accumulate in your jeans die between the times you wear them (depending on how often you wear a particular pair). This means that you only really need to wash your jeans when they get dirty or have been overused. However, if you're washing them regularly, there's nothing wrong with that, aside from how the pattern fades. So if you're not comfortable wearing jeans that haven't been washed in six months as the manufacturer suggests, you can throw them in the washer. You'll just have to live with a different fade pattern.
How Long Should You Really Go Without Washing Your Jeans? [HowStuffWorks]