A coworker asked me today what could be blowing the bulbs in his condo. Only the fixtures in his bedroom and closet are unaffected. All the other fixtures will blow bulbs if there are multiple bulbs installed. Two bulbs, it'll blow one. One bulb will work in any outlet in a fixture until a second bulb is put in. They replaced all the fixtures and switches except the fixture in his closet. The close is running the same bulb and fixture since he moved in and the fixture in his bedroom has the same bulb since he replaced the fixture 6 mo. after he moved in. I think he's been there a year.

Any ideas?