My Mother drummed it into me. The subject was raised almost every time I left the house. She would always mention the subject in the letters she wrote to me, during frequent times of separation. There were even occasions when she caused me a deal of embarrassment by asking me about it in front of my friends. No matter how many times she asked the question, my answer, although not necessarily true, was always the same.
"Yes Mum, I am wearing clean underwear".
Her concern however was not about my personal hygiene. Oh no. What she worried about was me being knocked down by a bus.
Apparently, at least according to her, I was almost certain to be knocked down by a bus if I was not wearing clean underwear. Nobody she knew, had ever been knocked down, or run over by a bus, whilst they were wearing freshly laundered underpants. On the other hand she had heard many stories of people being knocked down by buses, and, on being taken to hospital, shock horror, found to be wearing underpants that should have been in the dirty clothes bin.
Try as I might I could not convince her that she was talking nonsense. On one occasion, in an effort to disprove her theory, I informed her, somewhat callously I must admit, that I had been out in the same underpants two days running. She looked at me aghast, and with tears welling in her eyes, hugged me tightly, and exclaimed fervently, "dear God in heaven son, you are lucky to be alive!"
Mum has been gone for a long time now, but just on the off chance that some miracle occurred, and she actually made it to heaven, where she is able to look down on me, I try my best to live up to her ideals.
If, on a rare occasion, I am unable to find any clean underpants. I always make absolutely certain, not to go anywhere near a bus!