^^yeh^^ what sort of look are you going for? It's your hair, do what you want with it! If you are going to have to bleach it intensely before coloring (like, if you have really dark brown or black hair) and you don't want all your hair damaged so bad, do streaks. If you wanna make a more in-your-face sort of statement, do all of it. My favorite hair coloring website is http://haircrazy.info/ and if you are doing a bright, unnatural color, go with Special Effects hair dye unless you just want it to wash out in a month or two.
i colored my whole head of dreads a few times and had no problems, the dye actually helped it out, but my hair is super strong........
yeah, it does depend on how healthy your hair is before, and how much bleach you need to use, how much damage it does. Have you ever bleached/colored your hair before? It doesn't fry my hair either, even though I have to bleach it twice with the strongest kind of professional bleach. I also have very oily, thick, strong, healthy hair, which is conducive to that sort of mistreatment! The hair color itself is conditioning, it's the bleach that does the damage.
my hair laughs at bleach LOL my scalp is numb from years of dying my hair, but for now I am gonna let it go.............. but it definately does depend on your hairs origional condition