If you watch those shows about taking some woman who has a poor dressing style and "teaching" her how to dress fashionably and in style, often the most important remark is "choose the underwear that's right for you". This "underwear question" is often directed to the bra, and not as much to the knickers, probably because there's more form fitting in bras than in culottes (or maybe because boobs tend to sag more than buttocks... or Hyne knows...), and either way, with today's tiny thongs what support and molding would it do?
Now the bra question in itself isn't as simple as you would think. It's not like a pair of knickers where you can wear anything size ... M, just to give you an example, but first of all you have to know your size. In theory to do this you must take two measurements:
1. First you measure yourself right under the line of the breast and around your back. (Around where the bra would go.) I'll assume we all use the inch measurement for bras here. (So conversion need to be done in Europe and anywhere where bras don't start at 31, but at 70.) So, you take that measurement and if the number is even you add 4 to it, and if it's odd you add 5. For instance, you are 28 inches around and under the breast. 28+4=32. Also, if you are 31 inches around, you are 31+5=36.
2. Then you measure again around, but this time there where your breast if the fullest. This is usually at the height of the nipples. Here you take the difference between the first number (with the 4 or the 5 already added!) - known as bra band number - and this number, and so you get your cup size. One inch difference makes you an A, two a B, three a C, four a D and so on.
However if you've been bra hunting, you know that all that's nice and good, but the world doesn't work like that. Oh no, it doesn't. You can know by measurements that you ARE a 32C, and when you get to the store there's not one freaking 32 C willing to fit you, and instead you end up walking home with a 36B or a 31D or any other oddity. The style, the stitching, the fitting and even the advise from some salesgirls who actually urge you to just "fit them into the cup" isn't much of the help you need either. Not much people tell you either that the cup should hold the WHOLE breast, and that means that the cup should reach quite close to the armpit, otherwise it's uncomfortable, it can look bad (like you have more than two breasts, or like you are fatty, which you are not), not to mention the pain and other unpleasant things that it can do for you. (I've heard it can provoke all sorts of lumps in your breasts, but I've not hard evidence on this.) So that "grab them and fit them into it" isn't really a smart thing to do.
Bras should go when they are stretched out, have lost their shape or are no longer the right size for you. If you are a flat chested chick like me, you can manage to use sport bras or little fitting tops or even go around comando, but if you are a bit more "generous" neither of these is really an option. (Many flat chested women are already used to this fact and don't mind it, so a sport's bra that usually flattens you even more isn't much of a problem.) Either case, the time might come when you need a more "dressing bra", something a bit more structured, that not only keeps your breasts in place and safe from unpleasant jiggling, but also something that gives you a better shape and allows you to fill your blouses and dresses in a more flattering way. This day is when The Hunt starts.
Unlike with the easy tops and sports bras you can get at your local drugstore or supermarket - often using a simple measure system as S-M-L - the shopping for a real bra undertakes a whole quest that starts at specialized stores, lingerie stores and similars. Here, from the wide arrange of options that go from half cup, full cup, sexy, support oriented and Hyne knows what other options (mainly you go there and see those that go from whore-like sexy to nun-like orthopedic), you must or should have an idea of what you want to get. It's important for all girls and women to remember that the bra is for you, so either you pick the whore or the nun bra, that shouldn't be influenced by your marital status, but only by what you want to wear and what are you comfortable with. Recently I was bra hunting and one of the bras I tried on was a "push-up and show" kind that basically grabbed my small boobies and smashed them together in front of my chest and pulled them up. I bet it's sexy for many and I looked like I had HUGE boobs, but I wasn't comfortable with it. They were unnaturally pulled to the center pointing forward like Aphrodite from Mazinger Z. Probably a dozen women would kill for a bra like that, but I'm not one of them. Some like their breasts to touch and form a line between them, others don't. Some want something pretty to show off with blouses and dresses with clivage, and others want something that fits well a shirt and gives structure to a costume. And so you must put on your comfortable shoes, wear pants or skirt and a comfy blouse or shirt easy to take off and put on, and get lots and lots of patience.
Unless you have a favorite, secret little store that always get you what you desire, The Hunt implies visiting an endless number of stores, trying an even bigger amount of bras in order to find the one or the few ones that are going to fit your needs. Trying on several bras and walk out of the store with none of them is not unheard of, but also it may happen that you visit store after store and you simply don't see a thing that would appeal to you. Or there's also the case when you find something that looks pretty, you would really love it and when you try it out it stands weird on you. This can be one of the worse cases, particularly if you've been already hunting for a good bra for weeks. (This is also why guys have to be so tremendously careful when buying us underwear. It might look like something you would looooove to see on us - only to take it off later, of course - but then it happens that we would like to wear it and the pretty little sexy thing fits us oddly. So, you can buy us underwear, just make sure you can return it and change it in case of need.)
As noted earlier, recently I was on a bra hunt, and to add to all the difficulties proper of this task, I found yet another one: many stores don't work all sizes. And I'm not talking here of the bigger sizes (over D) or smaller sizes (under B), I'm talking about many regular sizes. In this recent hunt I found out that many stores have huge stocks of B cup sized bras with lots of band sizes. Now, you can be a 32C, that the salesgirls will try to talk you into a 34B or 36B. Sure, a B will make you look bigger because your breast won't fit into a smaller cup, so it will swell up all over the place, from the top, from the sides and you'll look like you've overgrown your bra, but in my eyes that doesn't make you look bigger, it makes you look deformed. Smaller cups actually flatten even more your bra and give you that unsightly multi-breasted look you really don't want to have. Or, you'll look fat and flat chested. (Bras supported with wires have the tendency to mark your breast making it look like your breast is only what fits the cup, and the rest is fat.) So, in addition to everything you've already gone through you've also have to start by FINDING your size at the store, and then hopefully find it in the type of bra you want to wear.
Yes, a good bra can make the difference. It can actually make you look slimmer, more proportionated, mark better your waist or even make it look smaller, it can make your clothes look like they were tailored specifically for you, it can make you look groomed and perfect... or it can make you look fat, deformed and tacky. It can make you look like one of the boys or like a goddess, so yes, when the time is right and you feel like it's time to get that bra, and commit to the hunt, you will eventually get That Bra (and you know what I'm talking about. It's the Perfect Bra, the Sexy Bra, the Woman Bra, the Hmmmm Bra), but aside from that, aside from making you look the way you want, it gets more meaning for you, because of - yes - the hunt and the dedication you've put into finding it.