I've edc'd my 6P for around 15 years and can only recall replacing the lamp twice. the last time was about 5 years ago and I put in a P61. I use it daily, sometimes short bursts and flashes, sometimes for several minutes and one time it ran flat in my holster burning a nice hole in the flap (why did I not catch on fire?). A new set of 123's and the P61 continues with no problems (but I always carry a spare and spare cells and spare light and spares for that)
Dave.