Sorry girls but I don't trust women who hyphenate their last names.
There are often various reasons for doing so. In my case when I signed my marriage certificate I just signed my name, the same way I had been signing it since I began signing my name, and so had to add my husband's last name at the end.
I only go by my married name, but legally my name is hyphenated.
I'm always late on these threads--
I was married once, and had mostly changed back to my maiden name but still had a few things in the married name, then my dad died. Within a week I had everything back to my wonderful Irish name. Should I ever get married again - which I just don't see happening, but should it - I'll hyphenate my last name in honor of my dad. It's a wonderful last name, and it's all I have left of him....