Whether most of your outings are to the grocery store or you're planning a road trip, your car is your base camp when you're out of the house. In addition to the tools you should carry to change a tire—a lug wrench, sealant, pressure gauge, and, of course, a spare tire—plan to stow a few extras you may need for other situations, to tide you over until help arrives. You should be able to carry all these items and still have room in your trunk for luggage.
Things to keep in your car:
Jumper cables: Don't assume the person who stops to help will have cables. Or you may be called on to help someone else. This dead-battery remedy can be a whole lot faster than waiting for the garage guy you call—and cheaper too.
Car registration: Chances are it's in your glove compartment, but maybe you removed it to prevent identify theft. Check your state's laws, as you may be required to have it in your vehicle at all times.
Owner's manual: Full of handy information if something suddenly goes awry, and when else do you need it but when you're with your car?
Flashlight: As helpful for finding a contact lens as it is for changing a tire on a moonless night. Get a crank-style so that you don't have to think about batteries.
Weather radio: When you can't get reception on your car radio or a cellphone connection, you'll be glad you stashed this radio. Obtain a hand-crank version, too. Also good when the power goes out at home.
Fire extinguisher: Again, this comes in handy for mishaps at home as well as any that happen in the car. There are automotive versions that don't take up much room.
Multitool: Almost a toolbox in your hand, this nifty item is like a Swiss Army knife and then some, with a mini saw, scissors, wire cutters, screwdriver, bottle opener, and more.
Duct tape: Still a go-to for temporary fixes to hold that muffler or mirror in place till you get to the garage.
Emergency warning triangles: Unlike flares, they're reusable. The bright orange is visible by day and the brilliant reflectors by night. They fold down flat when not in use, though we hope you'll never need them.
Emergency escape tool: The two-in-one tool fits in the palm of your hand and can cut a seatbelt or break a window. It should come with twin hammerheads to shatter and then clear the glass. Keep it in your glove compartment.
You might need more than that old adhesive bandage tucked in your wallet if you ding yourself while changing a tire or your kid scrapes a knee at the park. Get a kit from an organization like the Red Cross. It should have all the small necessities, including sterile gauze pads, antiseptic wipes, Band-Aids, and scissors.
Disinfectant face wipes: Useful for sticky hands or faces or when you need to sanitize quickly. Also prevents having to break into the first-aid kit.
Work gloves: Protect your hands when tugging at a tire or touching engine parts.
Cellphone charger: Maybe you carry one all the time, but for those instances when you forget it, you'll be glad for the backup.
Paper maps: Cloudy skies, a remote location, even an accident that blocks the road can hinder the effectiveness of your GPS. A road atlas will do the job wherever you find yourself; at the very least, pick up maps for your immediate environs.
Change of shoes: Sneakers or flats are a boon if you get stuck in a muddy environment or on your way home from a fancy party.
Poncho: Besides keeping you dry during an unexpected rainstorm, you can use it to protect the seat from a damp passenger.
Mylar blanket: Hey, this takes up hardly any space, so why not? Alternatively, you can keep an old comforter or a large bath towel in the trunk.
SEE MORE: How to Prepare Your Home for Emergencies
Small money: A few small bills—two tens and a couple of fives—and a roll of quarters provide backup if you lose your wallet or discover you're out of cash.
Carpet remnant: For tire traction in extreme mud or snow.
Paper products: Paper towels are good for cleaning up messy spills and such. A box of tissues gently takes care of the smaller stuff. While you're at it, a small notepad and a pen are a good idea, in case you need to fix a note to the windshield (with that duct tape) or hand out a phone number.
Plastic bags: Throw the used paper products in one, then dump it when you get home or to a rest stop. Also good for muddy shoes or a carsick passenger.
Matches: Necessary at one time or another. They're safer to tote and more dependable than a lighter. Stow in a plastic sandwich bag to maintain their effectiveness.
Food and drink: Stock nonperishable, nonmelting snacks like energy bars or dried fruit. Water bottles are fine in cool months but never in warm weather as heat causes the plastic to break down and release harmful elements into the water. Before you leave the driveway, place some bottles in the trunk in a small cooler with a few reusable ice packs.
Things to leave out of your car:
It's common practice for people to leave behind everyday items on the floor or back seat. As the stuff piles up, you may overlook the mail or extra electronic device you tossed there. However, these everyday items can leave you vulnerable to property as well as identify theft:
Cell phone: Even with password protection, loss of a phone puts at risk all the very personal details stored there. A clever thief can figure out a way to impersonate you and grab information.
GPS device: If crooks break into your car, and your GPS is programmed with important addresses, it could lead them to your house or the house of a loved one. Like your phone, this potentially stores a lot of private information; if you can, remove it when you're not in the car.
Mail: Even useless junk mail has your address, and credit card statements are a breadcrumb trail to your finances. Never leave behind these things, even concealed in a glove compartment.
Garage door remote: Okay, so if you keep this on the visor of your car you don't have to fumble for it when you pull in your driveway. But if a thief has your address then he can pull up and into your house.
Credit cards: Seems like a no-brainer, but it bears repeating.
SEE MORE: How to Install a Fire Sprinkler System
Gasoline: Some survival guides will advise you keep a small metal container of gas, in case of emergencies. We disagree. Never stow anything flammable, including disposable lighters or alcohol.
Medication: Besides the personal information on the bottle (your doctor's name and phone, your pharmacy, both of which have confidential information), here's another thing to consider: extreme temperature. Exposure to heat over even a small period of time will diminish the effectiveness of medication.