Well you just gave me another ten reasons why I DONT wear bras.
I always found them more uncomfortable to wear than new shoes, so stopped wearing one, when I stopped working in an office.
Most clothes I buy, I buy to suit "no bra", but if something does require something extra, I wear a nice camisole.
And....if ever I do need one, I have one in the bottom of my drawer, hoping I never have to use it.
And just as a footnote, I have never had big boobs, so gravity did not have much to work with.