Split ends occur when the protective outer layer of the hair, known as the cuticle, breaks down, exposing the inner cortex of the hair shaft. This can lead to a number of problems, including frizz, breakage, and tangles. While there is no surefire way to prevent split ends entirely, there are a number of things you can do to reduce their occurrence.
One of the most important things you can do is to avoid over-washing your hair. When you wash your hair too often, you strip away the natural oils that help to protect your hair from damage. Aim to wash your hair no more than 2-3 times per week, and use a gentle shampoo that is designed for your hair type.