If you have thin hair, clip-in extensions are a good option as they won't cause damage. However, it's important to choose clip-in extensions that are designed for your hair type. These extensions have fewer wefts of hair in each bundle, and less hair in each weft, making them more lightweight and easy to blend. They will also be more comfortable to wear. Thin hair can make the tracks of your extensions more visible, so ensure you don't place them too high on your head.