My mom is not hard to buy for. She likes books, music, jewelry, clothing—the usual stuff. But this year I’m getting her something she doesn’t particularly want (I know because I asked her), but I hope she’ll thank me for later.

It’s a blood-pressure monitor, and I’m getting it for two reasons: because she has high blood pressure and because I want her to be around for a long time. We recently rated these medical devices, which you can pick up at most drugstores for $40 to $150. Our Best Buy was just $40 (for subscribers).

People with hypertension or suspected high blood pressure should routinely monitor themselves, the American Heart Association says. My mom is on medicine for hypertension, but it’s still a good idea for her to have a home device so that she can keep tabs on her numbers and make sure the medication is doing what it’s supposed to do—keep her blood pressure normal. People whose blood pressure is not well controlled are more prone to getting heart disease, stroke, and kidney problems.

Our experts recommend that if you have hypertension, you should check your blood pressure at least twice a week at about the same time of day, and as often as twice as day if there are any problems or if your treatment has changed. We also offer advice about how to get the most accurate results.

I’m going to ask my mom to take the monitor to the doctor’s office to make sure she’s using it properly. Then I’m going to remind her to use it. It only takes a few minutes. I know that sounds naggy, but I can’t help it. She’s my mom, and I want her to celebrate many more Christmases.

—Sue Byrne, senior Web editor