My wife owns exactly one bra. same one for years and still in like new condition. she rarely wears it, preferring the natural swing and bounce.
I have 6 and she puts me in one about once a week, mostly it is a dominance thing with her. one sport bra and the others are lacy, girly show-off styles.
We are both 38C, perky, pokie nips. Neither of us has absolute need of the support.