As part of my duties back in my days of being a conservation field ranger, I was required to be proficient as a wildfire firefighter. I recently read a post from 
Some Background
Fires are not a constant through the year and tend to have a peak fire season of 4 to 5 months and when out of season (usually the winter months) our packs would sit patiently waiting for when we would require their service again. When I first started there, we certainly didn't have the best systems in place and everything was very chaotic and disorganised. Our gear was a disaster too. We rectified that after a while but I do not know how many fire lines I arrived at where my head lamp battery was not functional, the battery had run flat even though the headlamp wasn't switched on.
A Simple Fix
My manager came up with a cunning plan that we rolled out. Without having to remove the batteries that you would then have to find in your pack and put into the headlamp, inserting a small square of thin plastic between the battery terminal and the headlamp contact broke the circuit and extended the battery life. It also prevented the headlamp from being accidentally turned on while rummaging in your pack for something else and then running flat.
It may only be a small thing but this kind of small alteration can be quite effective. I've subsequently used this with my camera remote shutter release and it yielded the same result. It can be used for any battery powered electronics that you don't use regularly. Of course you would need to periodically check the batteries for expansions or cracks and battery acid leaks as any of these can ruin the contact plates of your equipment and damage it or fuse it. It's not the best practice to keep the battery in place, but in this instance it saved time and was an appropriate fix that I thought I would share. It's similar to disconnecting the battery of your car if you'll not be running it for a while which is also a smart thing to do.
Anyone got other useful battery tricks to share?