What happens if you don't wear a bra?

"If you don't wear a bra, your breasts will sag," says Dr. Ross. "If there's a lack of proper, long-term support, breast tissue will stretch and become saggy, regardless of breast size." ... Aside from the aesthetics, a lack of proper support (i.e. not wearing a bra) can also potentially lead to pain.

Is it OK not to wear a bra?

“It's OK to do whatever is comfortable for you. If not wearing a bra feels good to you, that's fine. If you feel that some support is needed, then maybe a bralette or a wire-free bra would be a happy medium at home. It all depends on what you're comfortable with.”