bag of holding.

When I was little, my mother told me to pack extra underwear on a trip. I was past that age where bathroom accidents were anticipated with preparedness.

I remember thinking it was silly because no one sees your underwear, as opposed to the obviousness of re-wearing the same shirt.

I know women should always pack extra underwear because the gods strike them with random menstruation whenever they darest put on shoes and leave home. (* statement somewhat tongue-in-cheek, but most women I know have tampons in their purses all the time.)

Personally I always bring extra socks, which makes no sense since I will happily re-wear socks and most of my socks would dry overnight when washed in a sink.

I usually bring about 50% more vitamins than I expect to need. (Hotel bathrooms being one of those places where the 5-second rule would not apply.)

Is there anything you bring extra of on a trip?