Your possessions own you. Nothing makes this more evident than electronic equipment.
The batteries in my marine VHF radios had always been a little finnicky, but when trips to the salty sea gave way to a long hiatus of inland navigation (if any) the radios and their batteries sat forgotten for...a long time, let's leave it at that. Similarly, after an active few years of mountain biking in which the group pushed the season well into November, we rode entire rides with lights, not just the last bit coming home after sundown. Then as we all drifted toward different forms of cycling, my battery light only got used for Nordic skiing at night. That meant long periods of storage, often with a longer period of uncertainty beforehand when I wasn't sure if I'd be topping up the charge any day.
A responsible battery owner tries to choose the least toxic options and recycle the dead ones, of course, but there's much more to the care and feeding of the rechargeable battery. I've discarded them for cycling, since my night missions are on roads at moderate commuting speeds and LED lights have improved so much. But I still have one light and two marine radios, none of which work at anywhere near full capacity.
In the case of all my rechargeable battery devices, I tried to remember to hit them with a housekeeping charge every so often, but it's easy to get knocked out of the rhythm. Also, with any nickel-based battery, memory can be a problem as well as self-discharge. They need to be run down and recharged. Battery University has some great articles on the subject. But lacking the tools to figure out why the batteries won't take or hold a charge when I tried to be meticulous about avoiding memory when I used them actively, I don't know what to do with my current pile of toxic waste.
I hate to chuck anything that works, but I'm a grunt when it comes to electricity. To do this thing right you need a battery analyzer and a scheduled program of maintenance. Even in storage the batteries perish from various causes. And the manufacturers cease to support them. Then you have a techie-looking, grossly expensive paperweight instead of a radio or a light. That's what I have now.
For cycling I have my array of Planet Bike Beamers. They take AA batteries, for which I can use rechargeable NiMH or alkaline. I'd like to avoid proprietary batteries completely in future devices. In fact, I'm starting to think fondly about oil or carbide lamps for the old bicyclette.