I have acquired about 40 lights mostly Emisar, Lumintop, Reylight, etc.
Many spend time in the garage, barn, cars.
Other than the car lights which may be needed at any time is it best to keep them in the house out of the fluctuating temps? Garage ranges from probably 25 degrees up to 100 in the summer.
I’d rather just worry about maintaining 2-3 lights that I keep on me or near me, and use them wherever as needed, vs having to worry about 10-15 lights I have hidden in various places like a crazed squirrel. 
Leaving lights to freeze/melt in temp extremes is never a good thing, especially if you only “remember” maybe yearly to check on them.
I… wouldn’t.
I agree with lightbringer, remembering where all of them are can be a problem, especially if they are e-switch lights that haven’t been physically locked out.
Generally speaking lights can get toasty from use so whilst it’s not technically good for a light to get hot (from use or external reasons) it’s not that big of a deal.
with the onset of winter (temps down to 10F) I recently checked the lights that had been in my car through the summer (100F). The one w Eneloop still worked. The one with LiIon had lost its charge and was OverDischarged, at 0.9V (it was unprotected and I had to take it to recycling)
I no longer store LiIon only lights in my car through the summer. Especially not UnProtected batteries. (unless the light will also run on AA Ultimate Lithium, Eneloop, or CR123 spares kept w the light).
example, I recently bought a Skilhunt H150 to store in my car. It is loaded w a Protected LiIon, but along with some spare Eneloop and Ultimate Lithium. If I find the LiIon dead, I have backup battery options.