Ask Our Experts

Should I warm up my car’s engine for a while before I drive on a cold day?

YES. GIVING THE ENGINE a chance to run before you head out on a wintry day is a good idea because it gives the oil pump a chance to circulate oil through your car’s engine and lubricate all the moving parts, according to John Ibbotson, CR’s chief mechanic. Doing this (plus good regular maintenance) can help keep your vehicle running past the 200,000-mile mark.

You don’t have to warm up the engine for more than a minute: Most cars take only a few seconds for the oil to lubricate the engine. So you should be good to go once you’ve settled into your seat, buckled up, and defogged the windshield.

You may be tempted to keep your car idling for longer than that to get the heat owing in the cabin (which can take around 15 minutes). But the fastest way to get your car’s interior to a comfortable temperature is to start driving. The engine heats up more quickly when you’re in motion. (And you won’t be using gas needlessly.)

No matter what the weather is like, don’t rev your engine for the rst few minutes of driving. Pushing a car too quickly after ignition is tough on your engine and can shorten its life span.

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… and watch for the answers. Is it okay to use an expired at-home COVID-19 test?

Even if the expiration date printed on the package of your rapid antigen test has come and gone, don’t toss it just yet. The Food and Drug Administration has extended the expiration dates for many tests, which means you may still be able to use yours.

The initial at-home tests were given fairly short expirationdate windows. That’s because regulators were trying to get them out to consumers as quickly as possible and weren’t certain how long the tests would remain accurate. But now, many manufacturers have completed long-term studies of their tests, and, as a result, the FDA has extended the expiration by several months past the printed date for some of those tests.

To nd out whether the test you purchased has had its expiration date extended, go to FDA.gov and search for “covid test expiration date.” You’ll nd a page with a list of tests by brand and, in a separate table, by lot number, detailing whether the expiration date listed on the package has been extended—and for how long.

If your test is expired and not on that list (or if the extended expiration date has passed), it’s possible that it might not be accurate. Get a new test instead: If you have Medicare Part B or private health insurance, you can get up to eight at-home tests per month reimbursed by your insurer, often with no up-front cost.

I want to monitor my heart rate and count my steps every day. Should I use a fitness tracker, or is a smartwatch more accurate?

When it comes to basic activity monitoring, such as counting steps and measuring your heart rate, our lab testing shows that the top-rated tness trackers are just as accurate as the top-rated smartwatches. In fact, certain tness trackers can actually be more accurate than some smartwatches: The $100 Fitbit Luxe (shown below) earns an Excellent rating in our test for step-count accuracy, while the $450 Apple Watch Series 7 receives only a Good rating.

Certain tness trackers can (like most smartwatches) track your sleep habits—and they typically run much longer on a single charge than smartwatches do. That’s great news if you simply want to keep tabs on your daily activity levels and your nightly zzz’s, because most tness trackers in our ratings cost between $30 and $150, while many smartwatches cost between $200 and $400, and some go as high as $750.

But if you’re looking for more sophisticated types of health monitoring, a smartwatch may be a better bet. Some can measure body fat and gauge your stress level—and will even guide you through workouts or count how many reps you complete for certain exercises, such as sit-ups. Smartwatches usually feature built-in GPS and let you download a variety of apps like Medisafe, a popular medication reminder.

To learn more about CR’s top-tested tness trackers and smartwatches, go to CR.org/wearables.