This is actually an interesting question. How do flashlights tell their age? Do they just perform 100 % until they no longer work (at which point the user has to decide whether it's worth the money to replace whatever is broken, if possible)?
I got the original Fenix PD35 960 Lumen myself. Absolutely love it, but I found myself needing more than the 960 when I changed job (landed on the 3000 Lumen Acebeam EC50 Gen. 2 - which I recently sold, and replaced with a 10000 lumen Fenix LR35R).
The PD35 still works great, and I even have a second one brand new in the box, sitting on a shelf. I really didn't see myself replacing it, ever, when I bought them, considering I came from a Streamlight Twin-Task halogen -> Coast G45 -> Fenix PD35). ^^
Flashlights has to be one of the very few things I replace or upgrade, BEFORE whatever I own prior no longer works (I want to throw away as little as possible). A 3000 Lumen flashlight can simply shine brighter than a 1000 Lumen flashlight. And I find myself needing more than the 1000 Lumen, well, I buy an upgrade, and either sell or set the prior light aside for less demanding tasks.