By the time you go through the estimated 500 hour life, you'll have gone through ~1000 batteries - unless you use rechargeables. (And I'd venture even with rechargeables, you'll burn through several sets.) If you consistently use the light for 10 hours per week (and that would be a lot for most people unless you use it professionally), that's almost 2 years of life. And it could last longer, or you might use it less.
I'm sure SF will replace the LED if it fails - but I think there's a fair probability that long before it does, you'll have replaced the KL4 head on the light with a new, improved, KL4 that's brighter, longer running, cooler, and whiter. (Note - I have no knowledge of SF's plans, but it's hard for me to believe they won't replace the Lux V with something better at some point as technology progresses. They are an innovative company.)
LEDs may eventually hit the wall and stop progressing, but until then, technological improvement is your friend. /ubbthreads/images/graemlins/smile.gif
I ran through all this myself before I purchased an L6. 500 hours sounds like nothing in comparison to the tens of thousands of hours typically promised by LED makers, but it's actually quite a long time for a flashlight.
