Battery: We wanted a monitor with a rechargeable battery that could last overnight, or at least eight hours, without being plugged in (a baby or toddler who is finally, blessedly sleeping through the night can sleep for 11 or 12 hours at a stretch, so more is better).Screen size: For local-video monitors, 5-inch screens are increasingly common, and they’re a happy medium between “big enough to see from a few feet away” and “small enough to fit in a pants pocket.” Smaller screens are okay if the price is right, but this was the size we focused on.We wanted to be able to maintain a signal up and down a flight of stairs, across the house, and on a patio or in a driveway, but we didn’t expect much beyond that.

Manufacturers’ range claims tend to be idealized. Range: Range is the main drawback of a local-video monitor, since audio monitors can roam farther out, and you can check a Wi-Fi–connected monitor theoretically anywhere that has an internet connection.

Type: For most parents, we recommend RF (radio frequency), or local-video, monitors, rather than one of the two main alternatives: a Wi-Fi (or cloud-based) model that you can check on your phone and bare-bones, audio-only speakers.

New york times wirecutter phone screen