The main cause of hair breakage in inferior hair extension systems are due to wax, metal or other hard compound hair extension bonds that do not flex when the hair is wet. The bond is so small and light weight that it is virtually undetectable and causes no stress on your natural hair. Correct application is also vital to prevent hair breakage. Specialist of hair extension said that keratin bonding process will not damage your hair if applied in the prescribed manner by a Great Lengths Certified hair extension expert. Great Lengths certified stylists undergo a rigorous training process. This depends on the method used to attach the extensions. There are several common techniques: fusion (attaching hair strand by strand), braiding, weaving, mini-locs, stringing, and using clip-in extensions. Generally, it will require several hours to attach a full head of extensions,how long hair extension last up to six months.