A root touch-up is a targeted colour service that recolours only the new regrowth at the roots, usually the first two to three centimetres, so it blends seamlessly with your existing colour. It is the most common way to keep permanent colour, grey coverage or a solid base looking fresh between full-head appointments. Because hair typically grows around a centimetre a month, most people return every four to six weeks, though this varies with your natural colour, how much grey you have and how sharp the contrast is.