I dont wear a bra very often.......but recently did need one and went to a lingerae shop to buy one.
What if found when I was trying them on, was that I needed a bit more in the back, and not as much in the cup....going down a size, made it too tight, going up a size and I did not fill the cup.....Finding the style, then the correct size and cup size combination, was just NOT happening.
Then the lady in the shop showed me these little strips of material, with hooks and eyes, that you clip onto the bra hooks, and give the bra anything up to an extra inch and a half in the back. OH glory be, I found a lovely style, nice snug cup fit, and with the extra bit clipped on the back, it felt very comfortable.
Not that it converted me...I still hate the darn things, and buy most of my clothes accordingly, so that they can be worn without a bra and still look nice. I'm lucky I am only a small build, and if I want to dress up my breasts and make them look sexy, I find a nice lacy camisole looks pretty.