It may surprise you to know that the majority of women are wearing the wrong bra size.
In fact, research suggests the number may be as high as seven in 10, according to Triumph Australia design manager Sally Danaher.
"Quite often the difference is small, say wearing a 10D instead of a 12D, but it can also be a significant difference and we have fitted women who have been wearing a D cup who should be in an F cup," she says.
"Not that this is a regular occurrence, but our bra fitters have reported days where they have not had one customer who was wearing the right size."
Wearing an incorrect size can be downright uncomfortable. Wires that dig in, fabric that cuts in under the arms or straps slipping off, are sure-fire signs you are sporting the wrong one, Ms Danaher says.
"Wearing an ill-fitting bra won't offer the right level of support. Breast tissue is delicate and once this tissue is stretched and damaged, it does not recover. This is why, over time, our breasts sag."
And although a bra is worn underneath clothes, the right size one can make a big difference to an outfit; lingerie will be invisible, the bust line will have a rounded shape and there will be a better overall silhouette, she says.
According to lingerie and swimwear specialists Four Seasons, the correct size can change a woman's body shape by improving posture, alleviating back pain, and creating a waistline which may have disappeared under ill-fitting bras and clothes.
All women should be fitted every six to eight months, as bodies fluctuate and change frequently, they say.
"It is always important for all women to be fitted by professional staff, at all stages of their lives - pregnancy, breastfeeding, menopause - or just because you haven't been fitted in the past six months."