Do you have one? We don't but my husband considers getting an Ajax systems set to get the house fully secured while I am not sure if we really need this. I mean, I am staying at home with kids so what could happen? We already have a fire alarm of course and all the other features of a security system like cameras, flood alarm, all the sensors, etc., it's not that cheap and if we invest in a decent security system I want to be sure that it brings significant benefits.