Thinning hair? Did you know you can make it appear thicker by the strategic use of color? By that I mean if you color your root line to deal with any regrowth you're also making the roots look a bit darker. Not only does this touch up your color it will also create the illusion of thicker hair. That's because roots that are a bit darker make your hair appear to be fuller and more dimensional.
Then how committed are you to your color choice? In other words are you ready for a permanent change or are you still dabbling so that semi_permanent color would be a safer way to go?