Dyeing is not great for your hair, but there are plenty of ways to decrease the amount of damage that you incur while dyeing it and to treat dyed hair so that it can be as healthy as possible. Dyed hair has more to do with style than fashion, I think. Fashion has more to do with trends and designers. Style is personal preference. Having dyed hair is part of beauty, too, because some people think certain colors are more beautiful or that their hair is more beautiful when the gray is covered up.