If you regularly use your clip in hair extensions and care for them well, they can last you anywhere between 3-6 months and sometimes even over a year. But again, like all hair extensions this depends on how well you take care of them.
Clip-In Hair Extensions do the least damage to your Hair. Just because you're adding a bit more weight to your hair and clipping in other materials doesn't mean you're damaging your hair.
Clip-ins are great for having fun with hairstyles, adding flashes of color, a sleek ponytail or a temporary fringe; and as there are no chemical bonds or knotting involved, they're a great non-damaging option for adding length to hair.