If your roots look like this, NOW! If you are darkening or covering grey hair with a solid color (NOT BLEACH OR HIGHLIGHTS) then you would book roots. If you do not want to put a solid color and wish to have your roots done in highlight form, then you would book highlights. If you are dark and wish to change your base color and add highlights, then you would book roots + highlights. If you are over 50% grey and wish to get highlights - but also cover the rest of your grey hair - then booking root + highlights is also your best option.