We don't tend to have power outages, and I rarely need a flashlight except for the occasional repair or search for something lost, but there isn't a room in the home without some source of emergency lighting at hand. Bathrooms have a night-light cum flashlight. Everywhere else is one or more flashlights and/or headlamps. In bedrooms, they are by the bed. All are LED lights powered by lithium batteries.

I have a reminder set up on the computer to change out batteries every five years, regardless. Bought online in "bulk" cost is not prohibitive. In the rare instance when I use a flashlight for an extended period of time, I replace the battery(ies) prophylactically.