If once a week is the answer then you might be able to cut down on the amount of washes you do. This article suggests that you can get away with washing jeans only every three months whilst still smelling socially acceptable. A team of volunteers in Australia agreed to wear a pair of jeans five days a week without washing them. They found that the jeans didn’t actually smell bad and that many stains simply wear off. Melbourne researcher Tullia Jack believes the findings of her experiment could have an impact on the environment as her volunteers saved thousands of litres of water and electricity in not washing their jeans.