If you’re using alkaline batteries, remove them from the flashlight if it’s going to sit unused for a long time, otherwise they’ll leak and cause problems. Store them near the flashlight so you can easily find them. Try taping the batteries to the flashlight barrel.
Pro tip: The best-performing flashlights are built specifically to use lithium-ion batteries or have nonremovable rechargeable batteries, which won’t do you any good if the power is out for a long time. Rechargeable nickel-metal hydride (NiMH) AA batteries maintain their performance better over the lifetime of the battery, whereas alkalines’ performance drops off more as they deplete, so buy some Panasonic Eneloops for $41. They’re better for the environment, but if they run out of charge you can still use regular alkaline AAs.
You may prefer to keep a headlamp handy. The Petzl Actik for $40 is my favorite model and has never let me down, from snowy mountains to dusty deserts. It runs on three easily found AAA batteries and has three brightness settings, the brightest of which is more than powerful enough for emergencies around the home.
Coleman discontinued our previous favorite pick, the Divide+ Push Lantern, so the Coleman 4D LED Camp Lantern for $19 is the next-best choice for not a lot of coin. Flashlights do a poor job when you need to light up a whole room or if you need your hands free for a task. This basic lantern offers a single setting of 54 lumens, with a runtime of 175 hours on four D-cell batteries. That sounds like a lot, but next to other full-size battery-powered lanterns, such as the Coleman Twin LED lantern that uses eight D cells, it’s economical. Fifty-four lumens is not what I’d call bright, but it is plenty bright enough for most tasks, even reading, while conserving battery life.
If you want to save batteries or just prefer hanging out by gentle flickering candlelight, keep a spare emergency candle or two. The Coghlan’s 36-Hour Survival Candle for $10 has three wicks that’ll last for 12 hours each. Keep a lighter or some matches nearby.
A Water Purifier
Most of the time, your water supply will work even when the power goes out. But major natural disasters can knock it out or damage it, and you might get dirty water. The Grayl Ultralight Compact Purifier Bottle for $81 is a solid and fast one-person filter that’ll last 300 uses—a total of 40 gallons—before you need to swap the filter. It’s what I trust when traveling to countries with no guarantee of water sanitation.