Something I've never seen anyone mention in these discussions is weight gain, and people being generally heavier, and the effect it has on how much people sweat.
I have a very elegant, slim friend who is 5"6 and a size 8-10. I've been on weekends away with her and she happily will shower every second day, on a camping weekend stretched it to three days because she didn't fancy the communal shower. I think she would normally shower most days at home but doesn't worry about missing one if it's convenient. I have a very sensitive sense of smell and I promise she doesn't smell at all.
We were once discussing why we had so much more laundry than her, and she also is happy to wear a top twice without washing. I'm the same height and about a 10-12, I couldn't rewear a top as it would feel sweaty, but I wouldn't wash a jumper if only worn once. Whereas my husband is a lot bigger, about 16 stone, and would always need to wash a t-shirt and whatever he'd worn over it, jumper, shirt, after a day.
I basically think the size you are correlates roughly with how much you sweat. People act as though there is a universal correct answer but in reality people live in different environments, ans their bodies produce radically different amounts of sweat. I don't smell after two days, but my hair looks greasy. I started washing it daily when I lived in a hot country where exhaust fumes would stick to your skin after a day being out. I could go a week without washing in this country and never be as grubby and grimey and sweaty as I was after an afternoon there.
I also think all the pressure to wash, and particularly to wash clothes, is a bit of a conspiracy to get is using more things and to keep women in their place. All these labour saving devices, and yet if you have people who feel they need to wash their entire wardrobe and pjs and bath towel every single day then they're as stuck under the tyranny of laundry as their grandmothers who were bearing carpets and using twin tubs. And it's always women self-policing each other on this too.