Whether you’re renting from one of the Big Three rental car companies (Hertz, Enterprise, and Avis), one of the thousands of smaller companies (which are often owned by one of the Big Three anyway), or a car-sharing service like Zipcar, the experience is pretty much the same: You make a reservation, inspect the car and sign off on its condition, and drive away.

If you’re like most people, that inspection is pretty cursory. We arrive at airports or carshare spots needing to hit the road, so most people will just walk around the car, take a video or a few photos, and get on their way. That’s really not good enough, because you’re putting your health and safety on the line, not to mention the success of whatever trip you’re on. While most rental cars are pretty well-maintained, you should do a lot more than a cursory visual inspection before hitting the road.

What to check

Nearly 70% of car renters have reported some kind of problem with their vehicles, so the chances that a more thorough inspection will catch something are relatively good. The moment you sign off on the car’s condition is the moment your fate is sealed—hidden damage can be laid at your financial feet, and problems with the car can make your journey miserable. Or even stop it in its tracks. Here’s the short list of things you must check.

Air conditioning and heat. It might not be mission-critical in some scenarios, but if you’re driving through hot or cold weather you don’t want to be miles away from the rental agency before you discover the climate control doesn’t work.

Seatbelts. Bottom line: Seatbelts save lives in car accidents. Make sure they all work properly before you sign off on that rental car.

USB chargers. Another minor problem that can become a major one if you don’t notice until you’re in the middle of nowhere with a phone at 5% charge.

Windshield wipers and washer fluid. Make sure they operate mechanically, and visually inspect them to make sure they’re not corroded, torn, or worn down. Then make sure there’s washer fluid by running a cycle, which will also confirm that the wipers are in good condition. Don’t find out your wipers are old when you get caught in a blinding rainstorm fifty miles down the road.

Tires. Visually inspect the tires and make sure the “low pressure” light isn’t on. To check tires without a pressure gauge, press your thumb into the tire—it shouldn’t give too easily. The tires should also not be noticeably flat on the bottom. You can also check the tire tread visually, or use a penny, and you should make sure the lugnuts are not loose. Finally, make sure the tires are appropriate for the conditions you’ll be driving in—rental cars often come from all over the country, and you don’t want to be driving on icy roads with summer tires.

All lights. Know how to turn on your headlights, highbeams, and hazards, and make sure all the lights are working, including brake lights and signal lights. Broken lights can get you pulled over and create a safety issue while you’re operating the car.

Key fob. Make sure the key fob that locks and unlocks the doors functions properly before you speed off. Don’t find out you can’t lock or unlock the car when you’ve parked it for the night.

Spare tire. Check that there’s a spare tire in the trunk (or at least a donut or emergency tire inflator kit), and that it’s in good condition—and that the lug wrench and jack are there, as well. While you might rely on the agency’s emergency roadside service, if they offer it, being able to get back on the road after a blowout or flat might be incredibly valuable.

Registration. Rental cars come from all over, so make sure the inspection sticker and registration tags are current. The police will pull you over if they notice expired tags, and that can impact your driving record, cause you a hassle with tickets and fines, see the car literally impounded and towed off—or worse. Check before you drive and insist on a different car if anything is outdated.

Know how to operate everything. We’ve all done it—you’re in a hurry to get going, and you’re on the highway doing 65 before you realize you have no idea how to turn on the highbeams, pop the gas cap, open the trunk, or turn on the hazards. More than 20% of renters admitted they couldn’t figure out how to operate their rental car in some way—so spend a few minutes familiarizing yourself with the vehicle before you head off.