Always in and charged, charged spares as well
Yes for NiMh.
No for liion. I mostly keep them in case at storage voltage until needed.
My wife was looking for a light on my shelf and was frustrated that none would turn on.
My EDC and mid ranged lights always have fully charged cells in them.
My large lights with battery carriers[ 3 or 4 cells] are Fully charged in a large pill bottle with a silica gel pack inside.Ready to go.
I’m about 50/50. I have a lot of lights that I keep batteries in because I often buy specific batteries for specific lights. I’m kind of an idiot though because I just charge them up and let them sit. When a light makes it back into regular rotation I’ll often do a refresh cycle on the batteries and a capacity test. So far despite years of neglect almost all my cells are holding up quite well.
All lights fully loaded and spare cells in a tool case, some fully charged some not.
Some lights have been sitting unused for years and when i finally think about checking them i find old cells i forgot about, like the Trustfire “flame” i used in my early days with this addiction. 
about 50/50 for me. I keep trustworthy cells in more often used lights but keep lesser used lights empty. I also try to rotate my cells throughout so one never sits long in queue with a full charge.
my rotation;
16-18650s,
2-18350s,
4-NiMh sub-C,
20+randomloops AA & AAA size,
4-14500 Li-Ion,
4-14500 LiFePo4,
s. I recently found an alkaleak puking all over the top of one of my speakers. It was next to the light I intended to use it with of course. at least it’s a scrappy-looking piece of woodwork to begin with.
and the light survived!
Haha, you might be a flashaholic if…
Cool 
I have many more flashlights than batteries. Batteries are expensive!
I keep batteries in my EDC lights, plus my “house light” (L6) and my Z1, currently. The only light that has a connected circuit is the FW3A, everything else is either locked out or has a mechanical switch.
All of my personal flashlights are stored with batteries. I might be an oddity though. All those lights use Eneloops and are either twisties or tail-clickies.
Around a hundred have batteries in and some spares of each type are charged and the rest of the batteries are at storage voltage in a metal cabnet
OMG I only have 10 batteries…Total!
One day you’ll remember that time… looking at a drawer full of cells. BLF will help you get there, don’t worry. 
Yeah thats strange, the other night I had a dream I'd own a box like this someday
Batteries in two EDC 26650 lights and two 18650, around 3.9 to 4.0 volts - they get recharged or replaced around 3.6 to 3.7v. No batteries in the other lights; their batteries are in cases at 3.6 to 3.7v unless their is a high wind advisory and then some backups and LT1 batteries get charged. We get a few power outages every year.
Also I have an 8-cell Maha NiMH charger and I keep cells in that.
Contemplating getting the Sofirn 8-cell NiMH charger as well, so I have more cells ready and waiting when the earthquake happens.
I’m not real sure about leaving cells indefinitely in a NiMH charger, but so far so good.
40+ Torches (now. Reduced them)
35ish have battery in, the rest are in boxes sans Battery.
Spare Battery’s.
Around 18/20. 26650/18650/14500/10500. plus a 4 set of Li-Po aaa’s.
Oh. and a half dozen half size cells too. To suit some short arse torches I tried.
Prefer the 18650 and 26650’s myself.
One thing I have noticed.
The second hand cells from lappie battery packs. (Sony. LG etc.)
ARE giving better. LONGER Power and time. That any Chinese cells
In standard. NOT super output torches, S2/C8/+ and others similar.
those cells do a great job in normal usage.
Yes to both. If its a light for use its kept with battery. If its put away and not in use/rotation/etc then its stored without a battery.
I’ve just enough cells to fill my EDC and the lights dotted around the house (maybe, 6 total). Remainder are stored empty in a small plastic tool-box.
I’ve a few multi-cell lights and only 2 sets of married cells, so invariably there’s a Q8 or the GT which is occasionally empty.
Any spare cells live in the battery box, mostly charged and ready to go.
I have more NiMh AA’s than I know what to do with… Obvious solution is to buy another AA fueled light 
Just because…
A single Li-ion is a cell, if joined in a pack of two or more and wrapped in a pack it becomes a battery… a battery of cells means more than one. Like a car battery is 6 cells.
Proprietary battery packs such as that in an Olight SR90 Intimidator have multiple cells linked together to form the pack, thus… a battery.
So, technically, virtually all our lights use cells.
Just saying.
edit: why anyone would keep such a volatile component as lithium in the potentially reactive humidity of a refrigerator (with FOOD?) is totally beyond my capability to understand!
Clip/magazine.