I'm reading HOW TO BE A TUDOR by Ruth Goodman. She takes you from dawn to dusk, describing how people lived in that era. What were their beds like? How did they clean their teeth? How often did they change their underwear? It's fascinating stuff, but the most entertaining part is that Goodman does what I think is called Living History. That is, she tries to live for a time in the way she describes.
One experiment involved trying to figure out if people smelled worse than we do because they didn't usually get in a tub or shower. While filming a TV series, she wore all the period clothing while doing hard work. She rubbed her body down daily with a rough cloth and changed her smock (ie her slip-like underwear) once a week. She changed her hose only three times in six months. Apparently even the camera crew who was going home to the modern era at night found her acceptable to be around.
One of her colleagues did the opposite. He followed modern hygiene routines, showering, using deodorant etc, but wore the same clothes for several months without washing them. He apparently reeked.
I am imagining a YA novel in which the teen character has a mother who does this.