It's supposed to have a lifespan of 8,000 hours but that may be wishful thinking. A "B" model airframe undergoing fatigue testing has sustained cracks in the rear bulkhead after just 1,500 hours. The F-35B is the short-takeoff/vertical-landing model being developed for the U.S. Marine Corps. In testing the F-35B is apparently faring somewhat worse than other models.
The Pentagon has been working for weeks to come up with ways to expedite testing and to fix defects in the aircraft.
New budgets and delivery schedules for the F-35 are expected to be announced on Monday after the Defense Acquisition Board meets to review the latest cost and test data.