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.
The audio quality is excellent, thanks to VTech's use of DECT 6.0, so you shouldn't hear any interference, static, or echoing when you listen in on your baby. Since the monitor uses a special frequency to relay the signal from the monitor in your baby's room to the parental unit, everything is encrypted and secure. No one but you will hear your baby.
If you sleep in the same room as your baby or live in a small enough space that you can always hear or see what your baby is up to, you probably don’t need a monitor. Otherwise, most parents enjoy the convenience a baby monitor provides—instead of needing to stay close to the nursery or constantly checking on your child, you’re free to rest, catch up on Netflix or get things done around the house during naptime. Monitors can also double as a nanny cam to keep an eye on your child and their caretaker.