Around 30% of adult males in the UK wear their boxers and briefs at least twice before they are stuck in the washing machine.
Worryingly, 8% of males admit they wear them three times before they are washed.
Women, however, were found to be far more hygienic, in a survey of British washing habits carried out by domestic appliance supplier Glotech.
More than 90% of women said they would wear their knickers only once before washing, and on average they wear a bra three times before sticking it in the wash.
Woman were found to own an average of 17 pieces of underwear, compared to 13 owned by men.
Unsurprisingly, perhaps, nearly 88% of women admitted that they do most the washing in their household.
Of those quizzed, 40% said they used their washing machine once every two or three days with most people putting it on in the mornings.
The findings come from a comprehensive study of the UK’s washing habits where 2,000 people were asked how often they cleaned their clothing and bedding.
The poll found that residents of East Anglia have the cleanest beds in the country, with a higher share (49.44%) washing their bed sheets at least once a week in comparison to any other region.
People from Scotland (36.08%) are least likely to wash their sheets once a week or more.
Women in the West Midlands wear bras the most times without washing them (3.21), while London women have the quickest turnover, washing their bras every 2.99 times they wear them, on average.
It was discovered Jeans offer the most ‘usability’, with more women and men prepared to wear jeans for an extra day - 72.95% - than any other clothing item, followed by jumpers (70.35%) and t-shirts (48.20%).
In other findings, South-East residents have the highest shirt turnover in the country, wearing them an average (1.67) times before washing, in contrast to residents in Wales, who wear their shirts longest without washing (1.92 times).
The Northern Irish own most pairs of underwear of any region in the country (16.12), while residents of Scotland own the least (14.71).
They survey also found that a sizeable number of those questioned still rely on their mother to do their washing.
Nowhere more so than in the North-East, where 11.11% of adults in the region still entrust their mums to ensure that clothes are washed, dried and ready to wear.
Also young working professionals aged 25-34 year olds are most likely to pay a cleaner to do their washing.
Some 66.35% of Brits wash their clothes every 2-3 days or more, with more running a wash in the morning (47.70%) than any other time of day.
Mikael Anderson, Business Development Manager at Glotech, said: “We were intrigued by the findings of this survey, which we believe to be the most comprehensive of its kind to be conducted in the UK.
“While in general Brits abide by the benefits of a bi-weekly wash, it is clear from the results that we are able improvise when we don’t have the time!”
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