ATLANTA -- The bra is a bare necessity for all women.

"The most technical product you wear, but it's the most personal product that you buy," said Susan Nethero, aka "The Bra Whisperer."

But, finding the right fit can be a major source of frustration.

"Straps are always falling down," said Erin Vanyo.

According to Nethero, owner of Intimacy lingerie, wearing the wrong bra is no laughing matter, and finding the perfect fit can yield big benefits.

"You'll be uplifted, and your bust line will be centered, and it'll make you look taller and thinner in a minute."

The biggest bra blunder: Wearing a band that's too big. Straps that are always falling down and bulging back fat are both signs that the band is too big.

Nethero said your band should be level all the way around, or lower in the back. She also said your bust should be centered midway between your shoulder and your elbow.

And, keep in mind that 90 percent of the bra's support comes from the band and only 10 percent from the straps.

Bra blunder two: The cup is too small.

If you're spilling over, chances are you need a deeper cup. Nethero said a D-cup is very average today.

"Every time we go down in back width, we need to go up in cup size in order to get the same sized cup," she said. For example, a 34C would be the same cup size as a 36B.

Bra blunder three: Wearing the same size year after year.

"Diet, exercise, hormones, pregnancy -- all of these are reasons for women to come in and get a bra fitting again," said Nethero.

And, if you're lacking volume, Nethero suggests bending over while clasping the bra to ensure that the cups are filled out.

Just a few minutes in the dressing room can boost your bust and your confidence.

"It's like a makeover in minutes and you don't have to diet, exercise or change anything else about your life," Nethero said.

Nethero said 65 percent of women have never been fitted for a bra. Intimacy offers free fittings at its Phipps Plaza location, but if you can't get there, click here for a tool that will help you calculate your size.