Jeans have come a long way since they were originally made as practical workwear for miners and labourers. Now available in every fit, colour and style, no wardrobe is complete without at least one pair.

However, figuring out how often they should be washed can be tricky. A study from the University of Alberta found the bacteria levels in a pair of jeans worn for two weeks were the same as a pair that was worn every day for 15 months, meaning washing them more often doesn’t make them…