You don't necessarily need a baby monitor before your baby comes home, however, I wanted to have one ahead of time simply because I didn't want to have to worry about going out and shopping for (and paying for) a baby monitor when we had a baby at home to take care of.
their breathing. If at any time your baby were to stop breathing (SIDS) an alarm goes off on the monitor and you immediately wake up and go help your little one.
-Price (you can purchase this monitor system for around $100. I found it on sale for $50).
-Temperature gauge This is an awesome feature. It's hard to know how warm/cold your baby's room is and there are definitely ideal guidelines for SIDS prevention related to baby's room temperature when sleeping (around 65 degrees F). This lets you know on your monitor how warm/cold it is in the room where baby is so you can adjust the temp accordingly.
-SIDS/Breathing Monitor In theory this feature would not be a con, however, we finally stopped using it after figuring out the MAJOR con associated with it. The pad tracks breathing patterns, and when breathing patterns stop...this super loud alarm goes off. So when you have a newborn sleeping in a bassinett next to you and they wake up 5X a night for changing/feeding/snuggling/etc. what happens when you pick them up? THE ALARM GOES OFF! No breathing sensed=Alarm. Absolute nightmare. You have to remember (in your sleepless stupor) to remember to switch OFF the baby monitor before picking up your little one OTHERWISE you will wake the dead.
-Battery Life I think it's difficult to find a monitor with awesome battery life that has a lot of features. The best battery life would probably be in your plain old monitor that just tracks sound. This one's not great...not awful....but not great.
So after M.D. moved into his big boy room and started sleeping in his crib at night, we realized that the sound-only option wasn't doing it for us. Sometimes we would lay him down to sleep and we'd hear noises through the monitor, but would have no idea what that meant. Was he awake? Was he making sleep noises? What was going on?! I really wanted to try a video monitor, but didn't want to pay hundreds of dollars to get one.
Price For a video monitor it is VERY reasonable priced
Quality As stated above, the picture quality is something I was very impressed with.
Future use The monitor itself is set up to have up to 4 cameras at once. Meaning, if you have more than one child (even if they sleep in the same room) you could have multiple cameras all feeding back to your one receiver
Battery Life If you're planning on using it all day without plugging it in you're outta luck. The nice thing is that it will last w/out being charged for both of M.D.'s weekend naps. We keep it plugged in & on all night long and plugged in & off during the daytime so ours is almost always charged. We've only run into problems on weekends when we forget to turn it off after he wakes up from a nap and don't have it plugged in.