Most lists like this are written for people moving in. This one isn't. It's for anyone who already lives in a house and has never sat down and asked what's actually missing.
The things below have one quality in common: you buy them once, they sit there doing nothing, and then one day they're the only thing standing between an inconvenience and an expensive, miserable week. Nobody regrets owning a shop vac at two in the morning.
They're ordered by how much you'd regret not having them. Where a specific product matters, the gear page has what to buy, grouped the same way as the sections below.
Safety
Fire extinguishers. You want two: one in the kitchen and one in the garage or workshop. Buy ABC-rated for general use — it handles wood, liquids and electrical. Mount the kitchen one near an exit rather than above the stove, because the whole point is being able to reach it when the stove is the problem. Check the gauge monthly and turn it upside down and shake it twice a year; the powder cakes at the bottom and the gauge won't tell you that.
A fire blanket. For a pan fire, smothering beats spraying. An extinguisher blasts burning oil around the kitchen; a blanket drops over it and cuts off the air. Keep it in a drawer you can reach without walking past the stove.
Smoke and CO alarms. One in every bedroom, one on every floor, and carbon monoxide alarms near where people sleep. Buy the ten-year sealed lithium units — they cost more and they end the chirping-battery problem entirely, which is the reason most disabled alarms got disabled. Alarms also expire: look for the manufacture date on the back and replace the whole unit after ten years, working or not.
Water leak sensors. Behind the washing machine, under the water heater, under every sink, beside the dishwasher. These are the places water damage starts, and all of them are places nobody looks. Get the kind that alerts your phone rather than just beeping — the leak that costs you money is the one that starts while you're away for the weekend.
Night lights with battery backup. A dark top step is where people fall. The versions with a built-in battery stay lit when the power cuts, which is exactly when you're walking around an unfamiliar-feeling house looking for a flashlight.
A first aid kit. One good one, in a known place, rather than three half-empty ones scattered about. Check it once a year — the adhesive on old bandages gives up and anything in a tube has a date on it.
Furniture wall anchors. Dressers, bookcases and televisions tip over, and the people they land on are usually small. Most flat-pack furniture ships with anti-tip hardware that goes straight in the trash with the packaging. If you have children in the house, this is the cheapest serious thing on this list.
An outdoor camera. Deliveries and break-ins are the obvious reasons. The quieter one is knowing what actually happened instead of guessing — when the package really arrived, who came to the door while you were out, what came down in the storm and when.
Emergency
Your water and gas shutoffs — and proof they still turn. Knowing where they are isn't enough. A main water valve nobody has touched in a decade frequently won't budge, and finding that out while water is coming through the ceiling is the worst possible time. Turn both off and on once a year. If a valve is stiff, a shot of silicone lubricant and some patience usually fixes it; if it won't move at all, that's a plumber's visit you want to schedule rather than emergency-call. For gas, keep the wrench at the meter, not in the toolbox.
Headlamps. A flashlight occupies the hand you need for the valve, the ladder or the child. One headlamp per person, stored somewhere you can find in the dark — which means not in a drawer full of other things.
A power bank, charged. Phones are the flashlight, the map, the radio and the way anyone finds out you're all right. Check and top it up twice a year, on the same day you do the smoke alarms.
A fire escape ladder if you have bedrooms above the ground floor. Buy one per upstairs bedroom, store it under the bed in that room, and deploy it once in daylight so you know how it works and that the hooks fit your windowsill. The first time should not be the real time.
Copies of the documents that matter. Scanned to the cloud, and the originals somewhere rated for fire. Deeds, titles, birth certificates, passports, insurance policies, marriage and death certificates. Fire safes vary from thirty minutes to two hours of protection — check what you're buying before you trust it with things that can't be reissued.
Drinking water. The standard guidance is a gallon per person per day for three days, which is more than most people picture. Store it somewhere cool and dark and rotate it when you change the smoke alarm batteries.
Food that needs no cooking. Tinned and dried, enough for three days, including anything your pets need. Rotate it the same way. The point isn't survivalism — it's not having to leave the house on a day when leaving the house is a bad idea.
A grab bag, already packed. By the door you'd actually use. Change of clothes, medication, phone charger, cash, copies of documents, something for the children. If it needs assembling, it won't get assembled.
A grab box for the irreplaceable. This is the one most lists miss. Everything you own falls into two piles: things insurance replaces and things it doesn't. Photographs, letters, the christening gown, your grandfather's watch. Insurance is excellent at the first pile and completely useless at the second. Put the second pile in one box you can carry in one trip, and keep it somewhere you'd pass on the way out.
A written plan and a grab list. Where you meet, who calls whom, what you take in what order. Written down, because nobody thinks clearly at three in the morning with an alarm going. Tape it inside a cupboard door.
Flood barriers. The water-activated kind swell on contact and go across a doorway or a garage opening in a couple of minutes. If you've ever had water come under a door, you already know whether you need these.
Maintenance
A year of furnace filters. Buy them a dozen at a time, write the size on the furnace itself in marker, and the job stops involving a trip to the shop. Filters get changed when they're already in the house and skipped when they aren't.
A gutter scoop. A plastic one, because a metal one gouges the gutter and the gouges rust.
A dryer vent brush kit. The long flexible rods with a brush head, used with a vacuum. Lint buildup is a genuine fire cause and the back of the dryer is not where the problem usually is — it's halfway along the duct where you can't see.
Both kinds of plunger. They are different tools. The flanged one — with the soft rubber sleeve that folds out — is for toilets. The flat cup one is for sinks and baths. Using the wrong one is why plunging sometimes seems not to work.
A hand auger. A small drum snake for sinks and showers. Most slow drains are hair and soap eighteen inches down, and this clears them in five minutes without pouring caustic chemicals into your pipes and then having to work in a sink full of them.
Caulk and a gun. Silicone for kitchens and bathrooms, exterior caulk for outside — they're not interchangeable. Also buy a caulk removal tool; new caulk over old caulk seals the mold in and fails within a year.
Spare batteries in the sizes your alarms take. Check what they are and keep a pack. The reason alarms end up disabled is a chirp at 2am and nothing in the house to stop it.
Touch-up paint, labelled. A small pot per room, with the room name and the finish written on the lid. Three years from now you will not remember whether the hallway was eggshell or satin, and a slightly wrong white is more obvious than the scuff you were covering.
Basic tools
A screwdriver set with both Phillips and flat in several sizes, plus Torx if you own anything made after about 2010.
An adjustable wrench. One decent one beats a drawer of cheap wrenches.
Two kinds of pliers. Needle-nose for the fiddly things, channel-lock for the ones that are stuck.
A tape measure. Twenty-five feet, locking.
A level. A two-foot one covers most things; the small torpedo levels are too short to tell you anything useful about a shelf.
A stud finder. Anything heavy on a wall needs one, and the anchors mentioned in the safety section need one.
A utility knife with spare blades, because a dull blade is how people cut themselves.
A GFCI tester. A few dollars, plugs into an outlet, tells you in a second whether the safety device actually trips. GFCIs fail while still delivering power perfectly normally, which means the outlet works fine right up until the day you need it not to.
A step ladder. The three-step kind, which covers smoke alarms, light fittings and the tops of cupboards. Chairs are how people end up in the emergency room.
Gaffer's tape. Holds like duct tape, comes off without leaving a decade of residue behind.
Zip ties. Assorted sizes. Cables, fencing, plants, trash can lids, and eventually something you'd never have predicted.
A shop vac. The one most homeowners don't own and should. The reason is water: a wet vac turns a burst pipe from a floor replacement into a wet afternoon. It also does the gutters, the dryer vent, the car and the workshop. If you buy one thing off this list, buy this.
The part nobody does
Owning all of it is half the job. The other half is knowing what you own, where it is, and when you last checked it — which is where most of this quietly falls apart. The extinguisher with a gauge in the red, the ladder nobody has deployed, the water that expired in 2023.
Pick a date — the clocks changing works well, twice a year, and you'll remember it. On that day: check the gauges, test the alarms, rotate the water and food, turn the shutoff valves, charge the power bank, and look at what's in the grab box.
It takes about an hour. It's the hour that makes everything above it count for something.
If you're starting from nothing, work down from the top rather than across — the gear page has the specific products for each job, and the first four items in the Safety section cost less together than most emergency call-outs.