With all the effort that has been put into making bras comfortable, it's easy to forget that not too long ago wearing a bra was hardly a pleasant experience. As a matter of fact, even today, women are dealing with the pain and discomfort that come with wearing ill-fitting bras, to the point where they will only wear them when they absolutely have to. Bras with underwire are known to inflict the most pain and scars, especially when the wire has come out of its protective strip.
No matter how you put it, saying that getting the right size of bra sounds like an understatement until you find yourself in that uncomfortable spot. The beautiful thing is that if you do get your size right, then no matter what you wear will look decidedly better. On the other hand, if you don't get it right, you'll be setting yourself up for a whole lot of different "situations".
If the bra is too big, its fabric will pucker and show that it's not properly "filled". And forget about filling it with pads, that's a chore you'd certainly rather dispense with. If it's too small, your breasts will give the impression of spilling out and the bra's fabric will dent into your flesh, leaving unsightly bumps under your clothing and making you look fat when you're probably just curvy.
Setting style considerations aside, the simple truth is that a bra's primary function is to give you support and give you back that perkiness that gravity is trying to take away from you. So in that regard getting a bra that's too tight can end up making your chest look flatter than what's pleasing to the eye. Getting too big a bra will probably make your breasts sag since they will most likely not be getting the right amount of support.
In order to achieve the best fit, it's recommended that you get your breasts measured about every three years. Afer all, everything else you wear varies according to changes in your body, so there's no reason why your breasts should be an exception. If you've gained weight, you'll probably need a bigger bra. If you lost weight, your breasts might have gone down in volume too.
There are also a few other things that can happens and may cause your breasts' size to fluctuate, namely pregnancy and menopause. While menopause's effects may be quite unpredictable, it's been widely observed that pregnancy usually causes breasts to grow in size and lose some perkiness.
Take the time to get yourself a bra that fits you and that you can comfortably wear for a whole day. It does make a world of a difference.