Every so often I encounter a home service provider that gets it right and this is one of them. What's not to like with ADT Home Security System?..You go to their website figure out how many and what kind of sensors you want, buy them and do the install yourself. If I can do it anyone can. I have dealt with other alarm outfits that try to sell you add-ons and unnecessary sensors but simplicity is more secure. I've been with Alarm.com for 5 or 6 years now, in two homes and I am totally happy. Customer support is always excellent. System is flawless!