The most important thing to look for in all kinds of baby monitors is audio quality. Regardless of whether you want a video-based baby monitor or not, you need clear audio so you can hear your baby properly. You'll also want one with sound activation so that you don't have to listen to white noise 90% of the time. With sound activation, you'll only hear the noises from your baby's room when there's something important to hear.
Gone are the days of silently peeking into the nursery to check on your napping baby and then, whoops, accidentally waking them up (“No, no, please no!”). A baby monitor uses a camera to watch over the crib, while you carry a handheld device that lets you know what’s going on with your child at any given moment, no matter where you are in your home. There are also other monitors that track sleep or breathing either with a clip or sock.