Hi folks,

Just to add my .02 cents worth on this subject.
I use lithiums in my flashlights that are exposed to cold and heat ( vehicles), and in other flashlights, and lanterns that are in my "blackout" kits.

I tend to use rechargeables in my EDC lights and carry a spare alkalines for backup.

Every 3 months, I will test the rechargeables batteries to see what their status is. Then I will batch them for a recharge so they will keep fairly fresh and useable in an emergency.
I use a battery tester called a ZTS Multi-Battery Tester to check for the battery's remaining capacity in %.

In the past, I used a volt meter but it was not as accurate.
I get good voltage but the the batteries usually didn't last long since their capacity was diminished due to age, etc...
even after charging.

So when there's a power failure at home, I tend to use the rechargeables first and then work my way down to the alkalines and lithiums.
Hope this helps!