The core of my prepper lights are a package of the Fenix LD12, Fenix LD22, and Fenix HL21 headlamp, they each have a low of 3 ANSI lumens with burn times of 97 hours, 110 hours, and 53 hours respectively, and they total up to 4 AA batteries, and with diffusers all make great lamps/lanterns, 3 ANSI lumens makes a perfectly fine flashlight, but all three lights have very bright settings with great throw as well.
With a solar charger and/or an adapter for the car, getting 4 batteries charged every few weeks should be no problem, and of course the AA is the world's most common battery anyway.
To me those three lights alone solve the lighting issue for long term emergencies of months and even years, and these are bullet proof, indestructible Fenix lights, so the fear of failure at the time of constant use and great need doesn't exist as it would with seemingly adequate, but cheaper lights.
I have more elements of course (don't all of us here, like dozens and dozens of them), the aaa lights and other long burning lights and battery options of course, but to have a core of such dependable, fail safe lights with such incredible capabilities and quality beams, gives a prepper peace of mind, and means that he can consider the flashlight niche filled so that he can move onto the next niche of preparedness.
In a survival situation, it may be winter and there may not even be heat in the house, the newest Eneloop AAs are good down to -4F, another strong point in favor of AAs.