Is Levi CEO Chip Bergh right to say you shouldn’t wash your jeans?

And how often should you wash the sheets?

When Chip Bergh, the chief executive of denim giant Levi Strauss, admitted he had not washed his favourite pair of jeans for a year, it got us thinking.

The 56-year-old had no qualms about  the cleanliness of his dark indigo trousers and advocated everyone else follow suit.

Speaking at a conference hosted by Fortune magazine in California on Monday, he said the jeans bought a year ago were “yet to see a washing machine”.

He added: “I know that sounds totally disgusting, I know it does . . . I have yet to get a skin disease or anything else.”

When he was asked how often people should be washing their jeans, he said “not very often” and said experts never put their denim near soap and water.

Instead, he recommended using a sponge or toothbrush to get rid of stains.

The Levi’s website repeats the advice, saying it is best to wash denim as “little as possible” to prevent shrinking and fading and help the environment.

If you give into temptation and have to give your jeans a wash, the company recommends turning them inside out to wash in cold water and leave to try on a line.

No doubt hygiene enthusiasts will be sticking to their normal routine but wearing unwashed jeans seems to have few ill effects.

The same cannot be said for unwashed bedding, which can exacerbate asthma, eczema and other conditions as dust mites breed.

A survey of more than 2,000 people conducted by Dunelm Mill last year found that just two in five of us change our sheets weekly - in line with recommended standards.

To keep the bed bugs away, it is best to wash sheets at least every fortnight at 60 degrees.