Wearing your underwear a second time, inside out?

I ran across this in a story – a character who cut down on how much laundry he had to do by wearing his underpants & undershirts a second time after turning them inside out.
Does anyone really do this? Why? Because it seems utterly wrong to me. The point of wearing underclothes is to have a layer of cloth between you and the ‘outer’ clothes that absorbs any, um, stuff (sweat, oils, dead skin cells, things we won’t specify) exuded by your body. This serves to keep the outer clothes cleaner, and thus you don’t have to wash/dryclean the outer clothes as often. Yes?

Which works, assuming you launder the underclothes. But if you turn them inside out, that all the stuff absorbed the previous day is now in contact with your outer clothes, right? Your outer clothes should end up just as ‘dirty’ as if you hadn’t worn any underclothes – you’ve simply delayed by one day. That is, Monday’s stuff ends up on your outer clothes on Tuesday. So, what have you gained??

If you only have ‘used’ underwear and need to get dressed, why not leave it the same way out? Or…skip the underwear.

I don’t get it.

eww I’ll put on clean underwear each day thanks. I’ll reuse jeans and overshirts without much issue.