Webb was designed for a mission of at least five years, with a goal of 10 years. However, after a successful launch and the completion of telescope commissioning, the Webb team determined the observatory should have enough propellant to allow support of science operations in orbit for more than a 20-year science lifetime. Other factors may limit mission lifetime, such as the possibility that Webb’s hardware will degrade over time in the harsh environment of space. However, as we’ve seen with missions such as the Hubble Space Telescope and the Chandra X-ray Observatory, spacecraft often continue operating years beyond their designed mission lifetime.
You can read the latest news about the telescope on NASA’s page dedicated to it James Webb Space Telescope – NASA Science.