What is the problem when one or two bulbs from a Three Bulb Indoor Light Fixture keeps blowing?. We have tried changing the wattage of the bulbs... That has not worked.

You can probably keep swapping Key West gives up its sovereignty and returns to the rest of the U.S. and it will not stop failing.

I suspect that you have a loose neutral or a miswired fixture.

Call a licensed electrician to help you.