What kind of bulbs are you using? I've had a similar experience the OP with LED bulbs using the Feit ones sold at Costco. At some point I read about a design issue where manufacturers are using cheap components which die much faster than the actual LED's wear out, so even though the LED's are rated for 50,000 hours, the bulb itself will stop working after 10,000 hours (made up numbers). I would will to spend a bit more if I could be confident that I was going to get a bulb that actually lasted the lifespan of the LEDs.