Avoid Uncolored Roots
How often you should retouch or recolor your hair at a professional salon can depend on how fast your hair grows. The average hair growth is half an inch per month. Your hair may grow faster or slower than this rate. To avoid uncolored roots from showing, you should recolor your hair approximately every four to six weeks.
Factor in Type of Hair Color
There are two types of hair dye, permanent and semi permanent. They maintain all over quality of color for different amounts of time. A semi permanent dye will last only four to six weeks. A permanent hair color can remain longer, up to twelve weeks without fading.
How often you recolor your hair at a professional salon is a matter of personal preference. If you want to avoid uncolored roots from showing through, you should have your hair retouched once approximately half an inch of new growth appears. However, depending on the type of hair dye used, you may choose a longer duration, since the all over color on the existing hair can last up to 12 weeks. You should avoid over processing your hair, which can occur if you recolor your hair in within three weeks or less.