My builder installed what Home Depot calls outdoor lanterns. They are essentially flood light fixtures mounted upside down to shoot light up the side of the house for a security/aesthetic effect. The bulbs use PAR 38 90 watts. After the flood lights started going out about every 2-3 months, I thought that maybe the sprinklers were hitting the fixture and possibly causing them to burn the bulbs out prematurely. I altered the sprinklers to minimize the amount of water the fixtures were getting (even though rain could always make them wet) and I'm still replacing bulbs every 2-3 months. Any thoughts on the possibility that they were installed incorrectly from the builder?

Approximately how long do the bulbs burn daily? Most bulbs of that type tupically have a life expectancy of 500 hours. Unfortunately lamp position does affect the life of a bulb, and bulb which point upwards tend to burn out faster because of heat distribution. As far a s being installed incorrectly... loose connections can create premature failure. You may consider changing to a cfl type floodlamp.

The bulbs burn from approx 7 PM until 7 AM and according to the specs on the box should last for 2500 hrs, or over 6 months. I may try the CFL type flood, but at $10 each, if they don't last long it's going to be expensive keeping 6 floods going.

I'm sorry I typed 500 instead of 5000... caught it when you commented. Tell me, do they burn out at nearly the same time? I know that floods or spots don't last nerly as long as regular incandescent bulbs, but those wouldn't work in your scenario. You man want to consider an enclosed fixture of some type, perhaps metal halide. Initial cost would be much higher, but you could easilly get 3-5 years of life from them.

I haven't been able to track if they're burning out at the same time. I'd say not. I'm open to some sort of enclosure - was considering something to enclose the lamps, but wasn't aware of such a device.