Characters are made up of a lot of details: age, weight, eye color, and hair pop to mind immediately. Do you put much stock into a character's hair? Don't you think it says something about them if their hair is long or short, dark or light, streaked or plain, curly or short? Does it say something about their family, or their independence and confidence?
One of my books, The Girl with the Thistle Tattoo, has a heroine with black hair with blue streaks. Astraea is rebellious and has a Goth bent. Her blue hair says something very particular about her.
But men's hair can be just as telling. Imagine how you'd feel about a guy who visited the salon to have his hair streaked every month. Or a guy with really long hair that he wore in a braid. Would these things give you hints about their personalities?
I've read any number of books with heroes whose hair I didn't like. I don't go for blond guys, for example, so in my mind I changed them to brunettes. That might be cheating on my part, but I figure the author might rather I continued buying her books, even if I had to play with a few details.
I'm a natural redhead, and when I was growing up and first started reading romance novels, so many of the heroines had red hair! It was much easier to put myself in their shoes when their hair was the same as mine. Do you feel that way, too? These days, I'm hesitant to make my heroines redheads because I don't want them to be too much like me. Weird how the screw turns.
So what kind of hair do you like to see in romance novels? Do you have a favorite hair type, or are you enraptured with any hair that seems to fit the character the author designed?