... even if you keep it charged up, keep it cool, like in a refridge and don't use em?
Also, is it better to store them charged up to 3.7V or store them with store with more of a medium charge?
I never charge to 4.2 volts anymore. I set my charger to switch from constant current to constant voltage at 4.1 volts. Doesn’t sound like much, but it makes a huge difference to cycle life. Also helps to reduce the voltage stress of spending time at or near fully charged.