It goes through a 13 point inspection to make sure that it still works.  You get a 45-day guarantee.  SO, if you are planning to purchase a refurb monitor, I might not grab one until closer to your due date.  That way you'd have a good long while to use it and try it out to make sure it works well. OF course, you can also make sure it works on yourself, or another child if you hold the light points on their foot or hand. If money isn't too much of an issue, I'd recommend getting the full unit as it does come with a better warranty.  Anything I've ever heard negative about the Owlet is about cords not working or things like that, so I'd prefer a bit more peace of mind.