A few common reasons are:
- Too much vibration when the unit runs. If this is the case, the unit may need additional bracing to the ceiling to hold it steady. Low end light bulbs have very thin filaments and these can easily break even with just a little vibration caused bay an opener. Try “rough duty” bulbs that can be found at most hardware stores.
- Sometimes the unit will have an electrical malfunction and send too much power to the light socket. In this case you probably need to call for service or replace the unit.