For just about as long as we've had surnames, the general rule has been that as part of the contract of marriage, the woman takes the man's name. Of course, these days that's become much more a tradition than a hard-and-fast rule, and although plenty of women do still choose to change their name, plenty more opt to keep their existing surname, and in some cases it's the man who does the name-changing now. The options don't stop there either: some couples might choose to hyphenate both their surnames together, or dream up something completely new. And I haven't even touched on same-sex couples, where the rules might be easier or harder, depending on how you look at it.
So which option to choose? Well, there's no right or wrong answer - or, to put it another way, the right answer is the one that feels right. But I'm not writing this to give you naming advice; instead, this post is going to be more concerned with something perhaps more boring, but rather important, and a source of perennial confusion: the legal side of changing your name.
At first, I was actually pretty confused myself by how this all worked. I assumed it must be some kind of deed-poll legal name change that was required, as it would be under non-marriage circumstances. But no, it's much simpler than that. And here's perhaps the most important bit to understand in all this: Within the legal contract of marriage, it's not about changing your surname, but instead adding an extra surname.
Okay, so let's use an example. Rose Smith is marrying Greg Jones. After they are married, Rose can legally keep her maiden name Smith; she can also legally use Jones now. The point is, if she chooses to go by Jones, she doesn't lose the ability to use Smith also if she wants to - she simply has two legally usable surnames now. To awkwardly paraphrase the Bard: A Rose by any other name (as long as it's hers or her partner's) would smell as sweetly legal.
And very important to make clear, this goes both ways. Greg can stay a Jones, but he can also choose to take her name, Smith. Most men probably don't even give this a moment's thought, but they are automatically gaining their partner's surname whether they like it or not.
(Probably worth noting also that in the hopefully unlikely event of divorce, this means that you can then revert back to your original name should you wish to, without much hassle. But that's quite enough talk of divorce on a wedding website!)
All of this is the reason why you can still use your passport when heading off overseas on your honeymoon, despite it having your old name printed on it. This is also the reason why some people, years after having changed their name in marriage, still have their bank account in their old name (procrastination is a powerful force).
You'll note that any other surname option beyond the bachelor surnames of each of the couple is not an automatic legal option, and that includes hyphenation of names. So anything like that can be used casually of course, but if you're wanting to use it for legal purposes, then I'm sorry Mrs. Rose Metallica-Forever, you'll just need to see about doing a name change the old-fashioned way.
(It hopefully goes without saying, but the above info is talking specifically about the circumstances of legal marriage in New Zealand. I have no idea what the rules around name change are in other countries.)
UPDATE 4/04/17: I have a little bit more to say about changing names as a result of marriage, with a couple of clarifications of this post; check it out here.