How often do you charge your sporadically used devices, like drills or portable game systems, to keep them ready for use and in good health?

I’ve been thinking about how to keep my sporadically used devices charged and ready to go without having to deal with dead batteries when I finally need them. I have a few tools like drills and some portable game systems that I don’t use on a daily basis, but when I do need them, I want them to be fully charged and operational. I was thinking about charging every sporadically used device every 3 months or so.

I know that letting batteries sit for too long can lead to degradation, and I want to avoid that. So, I’m curious about how others manage this. Do you have a regular charging schedule? Do you use any specific techniques or tools to maintain battery health? I sometimes read advice about "charge to 80%", but I have around 8 devices laying around that have just "red = empty, green = full" displays.