Speaking about how the friction in washing machines can distort a garment’s shape and colour, Professor Groves said: "I have garments in my wardrobe that I've had for decades that look brand new, simply because I know how to care for them."
The argument against washing jeans is similar. However, Professor Groves recommends putting jeans in the freezer in order to get rid of stains.
"Most people I know, when it comes to their denim, don't wash it at all. Which might seem strange - it's a pair of jeans that they might wear every day. But it's usually because they don't want the colour to fade."