Extensions should not damage your hair if properly installed and maintained. Whether you wear sew-ins or clip-ins, be careful while brushing and be careful with tangles. If you have a tangle, hold the hair while you brush it. If you are going to put your hair up, use a clip or an elastic hair tie that will not damage your hair. Also, if your weave is sew-in, make sure you’re having it sewn by a knowledgeable hair professional.