I live alone and am very sedentary so never get sweaty.
Shower about twice a week, plus whenever I know I am going to be physically close to someone e.g. dentist, doctor, friend coming round.
In hot weather I shower more often. In winter a bit less, except if it's freezing then I might shower to get warm.
On non-shower days, I wash "downstairs" at basin at night. I also, unlike others, wash my bottom after every poo. I don't think a bit of dry paper is sufficient.