Quentin Crisp famously said that dust didn’t get any worse after the first four years, but recent research at the Institute of Good Housekeeping has shown that levels in an occupied room actually reach a maximum  between 108 and 114 weeks, at which point anyone entering the room will automatically sneeze and redistribute the deepest dust across other horizontal surfaces.

The Institute also showed that dust has a number of beneficial properties, including improving thermal insulation, absorbing damp, deterring mice and improving digital TV reception.  By contrast, people living in dust-free environments are more prone to bronchial problems (especially if they smoke), falling down stairs, spontaneous combustion and tooth decay (known as biting the dust).