Every 3 days.
Once a day to be clean is a myth and is too much. More down to societal norms thanks to advertising from decades past (1920s-30s) than hygienic reasons.
"Zeichner and Hirsch say that
showering too often (particularly in hot water) can dry out and irritate skin, wash away the good bacteria that naturally exists on your skin, and introduce small cracks that put you at a higher risk of infection.
Both doctors say that
parents should not bathe babies and toddlers daily. Zeichner says that
early exposure to dirt and bacteria may make the skin less sensitive as you age, and prevent allergies and conditions like eczema.
If youre so inclined,
you can clean the grossest parts of your body with a soapy washcloth or cleansing towelette to remove odor-causing bacteria on non-shower days. (Grossest parts of your body = face, underarms, under the breasts, genitals, and rear end, according to Zeichner.)"
The more you shower, especially hot ones, the more you're dissolving the lipids in your skin that give you your moisture. If you're doing this once a day then you give less time for repair and natural oil production. The scrubbing with heavy towel use takes off the stratum corneum on your skin so you're left with dry and cracked skin.
Also, there's a difference between stinking that indicates you're dirty and just not smelling fragranced.