I have the Arlo system around my Front Door, Garage, and Back Yard / Pool Area. They are great!! Wireless, so you don't need a power source to run them. As someone said the batteries last a few months.
With the App, I am able to get alerts when ever there is action, and last summer when I was in London was able to see when the Dog Sitter came by and catch a glimpse of the dogs enjoying their vacation from us.