I grew up in Russia in 70th and 80th, and most people around me were wearing the same cloths all week long. On Saturday you would have a bath and done a fresh set of underwear at least, perhaps a shirt too.

Women typically would change a bit more often, and generally tried to have fresh panties every day (they would wash them separately from the main laundry). Men who considered themselves sophisticated would change _socks_ every day, but this was a minority. Nobody washed a shirt that they only wore once. Nobody washed pants until they had visible spots or smelled really bad.

And these were civilized XX century households, with access to hot and cold running water, gas, and electricity (but not always a bath or a shower, and rarely a washing machine).

Try wearing the same briefs and socks and shirt for a week, and you will show much you reduce your laundry load...