You buy bras that fit on the tightest clasp
Instead, choose bras by how they feel on the loosest hook. As the bra ages and the band stretches, you'll have the option of tightening its grip.
You haven’t been fitted in years
Your bra size can fluctuate from year to year with changes in weight, muscle tone, pregnancy, and age. Get fitted in person, suggests Christina Faraj, a professional bra fitter in Beacon, New York. "There are charts that will tell you how to fit a bra, but they're not fool proof," she says. "It's a very individual process." If you can't get fitted, start with the standard bra-size formula: 1) Measure your band size by looping a measuring tape from your back to front directly under your bust and across your rib cage. If you get an odd number, round up to the next even number to get your band size. 2) To find your cup size, measure loosely around the fullest part of your chest and subtract your band measurement from this bus measurement. The difference calculates your cup size (a one-inch difference is an A cup; a two-inch difference is a B cup, etc.).
You’re bubbling out of the cup
This means your cup size is either too small, or you've chosen the wrong style for your shape. For example, full-busted women should steer clear of demi bras, and instead opt for full-coverage bras that allow for a smoother look under clothing. When trying on bras, take a few moments in the dressing room to see how they look under a shirt. If you can see an indent where the bra cuts into your chest, move up a cup size or try a different style.
The band isn’t parallel to the floor
If your bra's back band creeps up toward your shoulders, it's likely a size too big and not giving you the proper amount of support, which can lead to shoulder and back pain. Go down a band size.
The underwire pokes and prods
This indicates that your cup size is too small. (Experts say most women are wearing a band that's too big and a cup that's too small.) The underwire on your bra should come from behind your breast tissue. If it seems like it's too narrow or digs into your skin, try on the next size.
You’re opting for wireless or seamless styles
Especially for fuller-busted women, these styles offer the least support. Opt for a sleeker look by shopping for a bra with seaming that's made of a material that's more rigid than stretchy.
You wear the same bra two days in a row
Although you don’t need to wash a bra after every wear, the elastic band does need a day to breathe."When [you wear a bra] two days in a row, it's like pulling on a muscle. It's going to strain it and it won't be able to snap back," Bobbie Smith, a bra fitting specialist for Freshpair, told the Huffington Post. Faraj suggests having four or five bras in rotation: nude and black bras for everyday wear, one fabulous lace bra, and a high-quality sports bra. For summer, she suggests a convertible-strapped bra. Wash each bra after every three wearings.
You toss your bras in the dryer
The best way to wash a bra is to hook the clasp and put it inside a washer bag. Never put a bra in the dryer, Faraj says. The heat will melt the band's delicate elastic.
You fold bra cups into each other
You wear a contrasting color under thin shirts
Something as simple as a camera flash or harsh lighting can draw attention to a white bra under a white T-shirt, or even a light-colored bra under dark fabric. Stick to nude bras under whites, and black or navy bras under darks.