That is the joke around our house, well it started with Tory's family. We know someone who wore her panties sidways. So it became a running joke that you could get 6 days out of one pair.
BTW Meike wears her backwards everyday.
Tory will sometimes tell my he is getting low on clean undies and I will jokingly say well just wear the pair you are wearing tomorrow, inside out.
I have actually heard of some women throwing their husband's underwear in the dryer when they are running low and they don't know the difference. Why not just wash them?