I have a weird thing going on in my house. We have pretty high line voltage, 125V on average. Some light bulbs in particular sockets last a long time, some hardly any.
The oddest one is the back porch. I wrote on the base, 1/14/02, the last time I changed it. I changed it last week, and it was just over 4 years old. They usually last about 4-5 years. On the front porch, the lifespan is insanely short. If a bulb lasts 6 months, it's a rarity, usually 3 months is it. The back porch light is on at least 3X what the front is, and a voltmeter confirms the voltage is almost exactly the same. They are in identical fixtures, and are both exposed to wind, but the back porch is rained on, and the front porch is covered by the roof.
The same thing goes on in the garage. There are two standard light sockets on the garage ceiling, facing down. A bulb on the left side lasts a couple of years, mimimum, but the right side eats bulbs at a one a month or maybe two a month rate. They are on the same switch, and the voltage measures the same. I put two of those "five year guaranteed" flourescent replacements in there a couple of years ago, and the right one blew at about 6 months, the left one just went a few days ago.
It's just weird, and annoying. The front porch fixture is a bitch to get open. it's warped slightly. It closes up fine though.