Your car is a big investment, one worth protecting. Anti-theft technology has become tougher over the years, helping drive car thefts from nearly 1.7 million a year in 1991 to fewer than 770,000 in 2016, according to FBI data.
But expensive anti-theft technology is useless without common sense. Between 2013 and 2015, nearly 150,000 vehicles were reported stolen with the keys left inside, according to the National Insurance Crime Bureau.
How much you should spend to protect your vehicle depends on the value of the car and how likely it is to be targeted by thieves. But it starts with being careful.
Check out a few options for protecting your car at every price range.
Less than $100
Something as simple as a security sticker costing less than $5 could make a thief think twice before breaking into your vehicle, said Marc Hinch, a California police detective and creator of Stolen 911, a site for posting stolen property.
"You can maybe make someone think your car has a tracking device," Hinch said.
If you have a frequently stolen car, like a Clinton-era Honda Accord, Hinch said he would at least get a wheel lock. Thieves have ways of getting past them, but seeing one may make them move along.
A wheel lock costs between $30 and $60, with the most popular brand, the Club, starting at $40.
More than $100
A basic alarm system starts around $300 but can cost as much as $1,000 depending on what you buy, Hinch said. A number of companies, including Avital, Python and Viper, sell car alarms in this price range that have motion sensors and alert your phone if there's a break-in.
Many alarm systems now come with cameras, like the Owl Car Cam.
"It's basically a surveillance system for your car," Hinch said.
The Owl Car Cam system starts at $349, plus a $99 annual fee. It won't necessarily stop a thief, but gives you a video alert if there's a break-in so you at least know when it's happening and have evidence to show the police.
A GPS tracker also won't scare off a thief — in fact, it's supposed to be hidden — but can help you track your vehicle if it is stolen. A tracker from Scout starts at $99, plus $15 a month.
LoJack is another, more expensive, vehicle tracking system that uses old-school radio tracking in addition to GPS technology, Hinch said. It starts at around $700, but is available cheaper at car dealerships, he said.
If you have a higher-end vehicle or a work truck loaded with pricy equipment, you may want to shell out for a Ravelco, which starts at $495, Hinch said. A Ravelco device won't allow your car to start unless you have it plugged into the dashboard, making it difficult for thieves to hot-wire the vehicle.
Your auto insurance company may give you a discount for installing an anti-theft system. Contact your provider to see if you can score a lower premium. (See what other car features can lower your premium.)
A little extra vigilance costs nothing, Hinch said. Don't keep anything a thief would want in your car, even in the trunk.
In popular tourist areas, thieves will keep an eye out for people who move their bags to the trunk, Hinch said.
"They'll just break into the car, open the trunk, steal the bag," he said.
If you must leave something in the car, put it in the trunk away from your destination, Hinch said. When Hinch goes to lunch with his kids, he has them put their stuff in the trunk before they arrive at the restaurant.
Don't leave your car running unattended. Thieves target people who do this to warm up their cars in the winter or when they're running into a store, Hinch said.
"They cruise around at certain times in the morning and look for cars warming up," he said.
They may try to steal your car or grab any belongings inside, like a purse or laptop.
Any safety measure is better than nothing, whether it's a fancy alarm system or just being more aware of your surroundings, Hinch said. Criminals look for easy opportunities.
"A little vigilance can keep you from being that opportunity," he said.