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Recall. When you hear that ominous word in the news, it portends dire consequences. But are recalls urgencies or emergencies? What’s the best way to stay informed? How long should you wait before calling your dealership? Here’s what you need to know.

One big recall involves 7.8 million vehicles and counting—from BMW, GM, Honda, Toyota, and other automakers—in which air bags made by the Japanese supplier Takata are prone to explode in collisions, spraying passengers with shrapnel, sometimes with fatal results. Last year GM also recalled 2.6 million small cars for defective ignition switches that could cause the car to turn off while being driven. In 2009 and 2010 Toyota recalled more than 10 million Toyota and Lexus vehicles for problems that led to unintended acceleration. In 2014, through autumn, automakers announced more than 500 recalls affecting more than 50 million vehicles.

But many recalls are for less than perilous reasons. Sometimes they’re for something as benign as a mislabeled sticker. Or durability tests find a suspension spring could wear out prematurely.

Even when a recall is issued, often there’s little likelihood that a part will actually fail. Indeed, a vast majority of affected cars will never experience the potential problems outlined in a recall notice. But automakers are taking fewer chances these days, given a more aggressive regulatory environment and plaintiff lawyers having more success in defect litigation. And no manufacturer wants to risk the same fate as Toyota, which paid a $1.2 billion settlement to the Department of Justice for dragging its feet during its unintended-acceleration recall process.

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Learn more abut recalls in our guide to car safety.

When a manufacturer initiates a recall, whether for a minor problem or a biggie, it sends a letter or e-mail to car owners instructing them to take their vehicle to a dealership to have replacement parts installed, free.

The replacement installation should go swiftly and smoothly. But sometimes the scope of a recall is so large—as in the case of the GM ignition switch—that there’s a long waiting list for service or replacement parts. In that case, it could be weeks or months before a dealer can fit you in. The dealership should notify you when it has the spare parts in stock. Once an automaker alerts the National Highway Traffic Safety Administration to a recall, it has 60 days to notify owners, regardless of whether the spare parts are in stock. But you can be proactive by calling your dealership’s service manager to make an appointment to service your car.

If there’s a delay for a repair, the most obvious questions to ask are: Am I putting myself in danger when I drive? Or should I just park my car until it can be repaired? That’s when you need to read the recall notice closely.

Check to see whether the recall involves a key operating component, such as the acceleration, brake, steering, suspension, or fuel systems. Some defects might create a nuisance but don’t pose an immediate danger. If you’re unsure about how to assess the risk, call your dealership.

The time to worry is when an automaker tells you to stop driving the vehicle. In that case, it should tow your car to a dealership and provide a loaner. But that situation is exceedingly rare.

In the case of the air-bag recall, there was no such order. If you’re concerned about your passengers, leave the front seat empty, which will deactivate that air bag.

Most recalls are initiated by automakers, but drivers play a role, too. If you think your car has a safety defect, file a complaint right away with the automaker and the government. Provide your vehicle’s make, model, year, and vehicle identification number, and write a brief description of the problem. Contact NHTSA at safercar.gov or by phone at 888-327-4236.

This article also appeared in the January 2015 issue of Consumer Reports magazine.

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