Image and audio quality: We wanted a high enough resolution to make out facial features in the dark, at more than a few feet of distance, and (obviously) in daylight as well. The screen itself did not need to be incredibly high-resolution, but we wanted a size that would be easily visible on a nightstand. For all monitors, but especially audio-only options, we wanted to be able to hear everything clearly at the lowest volumes.
Wireless encryption: This ensures that no one else can tap into your monitor’s “feed” and see what’s going on in your house. WiFi-enabled monitors are great for portability and range, but may be more susceptible to hacking. If you go this route, be sure to secure your home wireless network and keep the monitor’s firmware updated. Otherwise look for digital monitors with a 2.4 GHz FHSS wireless transmission.