The first thing you need to consider is whether you want to have an audio-only baby monitor or one that incorporates video. Some parents choose to use smart home security cameras that send a video feed and alerts to their phones via an internet connection instead. Your choice largely depends on your budget and how high tech you want the baby monitor to be.
The BabySense (and other mattress sensors) require a hard surface under the mattress to work, and they don't work with all mattress types so you'll need to research your mattress to ensure it is compatible. This option is also not good for travel because of these special considerations. This product doesn't have a parent unit which means the alarm happens in the nursery with your little one and could be traumatic to sleeping little ones. If you want a movement device that works well and has a longer life than the wearable options, then the BabySense 7 is a great way to get the job done with minimal fuss.
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.