Shortly after I bought my PA28-161 about 28 months ago, I had to replace the landing light. So I bought two of these. Research indicated that these lamps will last about 25 hours or so. That service life was accurate for the first lamp. The second burned out after about 20 minutes of use. The filament is clearly separated. Very happy with the life of the first one. Very disappointed with the life of the second.
This is a great alternative to the std 4509. It has a rated life of 100 hrs vs the 10 hrs youll get from the 4509. The quartz bulb will give 100 hrs, as long as it is kept cool - dont leave it on on the ground. Also, for a taxi light I use a 4595, and run it during all flights since its rated for 300 hrs. this bulb has a much wider beam, 14 degrees vs 10 for the 4509, so taxiing at night give a wider beam.