After installation, you have to go to your stylist to have your extensions moved up every 2 to 3 weeks. On average, your fusion extensions should last from 4-5 months. There’s no way to determine precisely how long your fusion hair extensions will last since their longevity depends on the texture of your hair, the installation process, and how you care for your hair post-install. If you have a healthy hair care routine and do not use abrasive hair products or lots of oils, the extensions will last closer to the five-month mark. You’ll know that it’s time to throw your extensions out when they begin to look dull, stringy, and unruly.