YOU HAVE TO BUY THE RIGHT SIZE AND CAN'T BE CHEAP ABOUT IT!
I took my DD 12 to get her first, thank god there were fitters there to measure her, what I chose was wayyyyyyyy off
it was pure magic to get the right one, even for me I was like WOW!
here is an article on the subject:
How does one find the perfect fitting bra? Obviously the instructions I was taught for measuring my breast size is outdated or incorrect. Can these bras be found in your local Wal-Mart & Target stores or does one have to go to a more upscale lingerie shop to get the perfect fit? Your expert advice will be appreciated.
It is estimated that more than 75% of American women wear the wrong size bra. Many women don't know how to find the right fit and even when they do, they forget that with age, motherhood and other hormonal changes your bra size may need changing as well. Here is what I have learned. I hope it helps!
To get the right fit:
Bring a tape measure around your back, stand up straight and measure just under your breast (top of ribcage) where the bottom of your bra band should lay.
If this number you measure is even, add 2 inches to it; if the number you measure is odd, add 3 inches to it. (So if your ribcage measurement is 31" you would add 3 inches to make your bra band measurement 34". If it is 32" you would add 2 inches to make your bra band measurement 34" and so on.) You have now determined your bra band measurement.
This is the most important measurement because the majority of your support must come from the band. If the band is too loose the support rests on your shoulders and that inevitably causes back and shoulder problems.
Now take the tape measure and measure around the apex of your breast (nipples). Subtract this number from your determined band measurement to determine your cup size. 1" difference is an A cup, 2" difference is a B cup, 3" difference is a C cup, 4" difference is a D cup, 5" difference is a DD cup and so on.
When trying bras on, (and you must try everything on, even if you know your bra size) you should fit to the first row of hook and eyes in the back. This way, there is more adjustment room for tightening when the bra stretches out a bit. The fit should not be too tight or too loose... you should be able to pull it out no more than a couple of inches when tugging at the back.
The straps should be tightened to allow 1-2 inches of space when tugging up on the strap.
When putting the bra on, bend over and pull all of the breast tissue from the underarm and underneath the breast to fill the cups completely.
Jiggle the wires into place if your bra has them. You want them to hug the body and cradle right under your breast.
Also, make sure:
The under wire ends at the side edge of your body. It should reach for your underarm.
The side of the cup hugs your body
Everything fits
not too tight and not too loose
There are no wrinkles in the cup or anywhere else
The back band doesn't ride up
The center band between the cups lays flat against your sternum