I assume the OP is talking about li-ion cells. I have batteries in 10 or so lights scattered around the house that are fully charged all the time. I also have about 15 that are charged to around 4.15v in the event that I need a battery immediately, and another 50 or so laptop pulls that I keep at around 3.7 volts.
Only the ones with mechanical lockout. I just did my tri- monthly check on them and found 2 lights discharged down to around 3.51v so something was making contact. There are 2 that don’t have mechanical lockout that were at 4.12v after 3 months.
Maybe half of my lights are ready to use with full charge batteries and i have a bunch of batteries (pulled from laptop or other appliances battery packs) in stock, some at full charge, some at "storage" level
All my lights have charged batteries. All my AAA lights have lithium primaries.
The stored Li-ION lights are mechanical locked out (if possible).
If not possible (Cu, SS, Ti) I put a small plastic cup under the tailspring.
Only the lights in my rotation are not locked out.