Women’s breasts come in different sizes and shapes, which means that even if two women measure themselves, and find they should wear the same bra size, the same style of bra might not work for both of them. Bras are very much an item that needs to be tried on for fit.
In addition, even though bra manufacturers CLAIM to use the same sizing system, they don’t. They are liars. Big, big liars. Hell, if a woman wears a 34C in Acme Company’s “Lovely Lift” line, that doesn’t mean that she’ll wear a 34C in any of Acme Company’s other bras. When she tries on bras, yeah, she can start by trying 34Cs in various styles…but they might not fit right.
Bras tend to stretch horribly. Part of this is just the nature of the material they’re made from, and part of this is because most women tend to throw them in the washer and dryer. It’s OK to wash bras in the washer, on a gentle cycle, with cold or lukewarm water, but heat will destroy the elasticity of the bra. So women, air-dry your bras! It’s best to handwash bras in cool or lukewarm water and then air-dry, but who handwashes stuff any more?
I used to fit bras, and the majority of women that I fitted were indeed wearing the wrong size bra, and quite often, the wrong style, too.
Oh, and JUST when a woman has found a bra that fits properly, and does great things for her bust, then the manufacturer will discontinue that style. It’s like a law or something.
I, personally, hate underwires and think that they are instruments of torture. I would claim that Satan devised these things to remind women that they are the ones who accepted the apple, but I’m an atheist. However, other women love underwires. At any rate, it seems that bras are either aggravating to wear, or ineffectual, or both. It seems that we can’t design a bra that is both comfortable AND effective.