in regards to batteries I have several LED flashlights as they last longer on a charge.
I also have about 100 chem lights and I don’t know how many candles.
a few wind up lights with radios as well.
I have had occasion to use them and my friend who had standard light quickly ran out of light and batteries.
I had plenty of batteries and a back up of rechargeables with a solar charge for charging little things like cell phones, GPS, batteries, etc.
I will be viable much longer than others and I have no interest in sharing as that would make me a target or put me in the position of being a leader over those who would not take my lead or command. to which I would say “you have to leave the island”.
The fairly cheap solar chargers are something most people don't think about. I have several, one dedicated to keeping the batteries on my bass boat on trickle charge during the winter. They work great.