The simplicity of the original photonlights is one reason they are so long lasting. I mean, if you replaced the battery, you would find the 2 piece housing, the battery, and an LED whose leads were bent a certain way, and clipped. That's it. The design intent (I think) is to have illumination with you to see things for a brief time; not a torch for reading novels.
In my younger days, an amber photon would get me home through unfamiliar forest at night because I had a fawn Doberman, who when told it was time to go home, would start heading home. Numerous times I had to tell her to slow down so I could see her with the photon light, even when the battery was low. All that was necessary was to briefly turn it on to see the path and her. If I left it on for too long, it would dim. But that, you see, was the beauty of a non regulated light. I could pinch it on briefly only when I needed it. And it lasted like that a long time.
The photon micro light II, at least the one I have on my wife's keychain, bought years ago, is simply constructed as well. Using a very small screwdriver to open it, one could see a clear plastic switch is used to press one lead from the LED, continuously on the battery. Yet one can still use the momentary pinch function. Simple.
The Freedom circuitry has the wonderful variable brightness. It will step down when the battery depletes. I don't think a near finished battery will get a person out of the woods unless the one wielding it keeps the lumens as low as possible. This is not a torch that someone can change the batteries in the field very easily although it could be done. It shines as a backup and for 'quick looks'.
No doubt, other people have used theirs in other, very useful ways.
That was the only dog I ever had that would lead me home.