I like Captain Ned's suggestion ... for a number of reasons (furry friend, mobile alarm, sympathetic listener, etc.). In my own case I have dogs on every side of my house that bark at all sorts of things, including me turning on my back porch lights! I do not have a dog myself now, but I had one when I was very young and learned they can be very protective of their master and their master's property, especially when that property is behind a 6 (or higher) foot fence.
When I decided to add video cameras to my home I opted to "flex my geek skills" (retired server & network engineer) and built up my own system of IP-based POE cameras backed up by a quality UPS system. Yes, that meant pulling cable everywhere, but I firmly believe that if I can watch my cameras wirelessly then so can anyone else that is "creative" (and even hack them). Another thing I do not like about wireless cameras is maintaining the batteries; the darn things can "go weak" at the worst possible times. I can also add the privacy concerns of uploading the video to "the cloud" so that I can view it; some cameras work like that. Add to all of that the hassle of battery maintenance and finding a Wi-Fi channel that is not already overloaded (RF congested) with other users and the behaviors of RF signals around structures, and the end result is a sometimes unreliable video signal; my neighbor experiences exactly those problems with his system.
My "video server" is based on the open source software "zoneminder" (http://www.zoneminder.com
), a very "flexible" piece of software. In my case I have a (Debian) Linux-based server with "zoneminder" on it that is built to the "zoneminder" developer's advice of "more cores, not more clock speed" makes "zoneminder" the work best with 1 core per camera being optimal; counter-intuitive I know, but that dev is right in my experience. I can configure "alarm zones with motion detection" or even switch any given camera into full-time "record" mode, and you don't need to run cameras at 30fps when 8fps or even 6fps is satisifactory for motion detection and reasonable identification of a suspect. As for "central monitoring" by a 3rd party? Don't want/need it as a VPN to the house network handles remote access and any privacy concerns while avoidjng all of the risks that go along with "broadcasting" one's home cameras to the Internets. Also, there are 3rd party apps for "zoneminder" that you can run on your mobile phone. Nice thing about IP-based cameras is the fact that most have directly accessible video feeds, once you figure out the appropriate access method (generally a URL, but sometimes an added app or driver is needed to view the stream).
Ok, I sound like an advert for "zoneminder". I have absolutely no connection to them, I SWEAR! I just happen to like the software because it allowed me to "geek out" while building a Linux-based server and video camera network.
A few further thoughts. Consider your camera placements carefully; lay them out on paper first and consider "field of view". Remember that "night vision" on a video camera is not great; limited viewing distance and a "halo" effect in images is possible without added IR lighting (more wiring to do). You really don't want your house looking like a fortress or a prison with cameras everywhere. You really don't want to place cameras where they are easily accessible by a criminal (cameras can be costly), unless they bring their own ladder (kind of obvious, no?). Try to understand human psychology regarding approaching a door; people rarely look up because they are focused on the door/entryway and/or door bell, but you can get a good visual from an overhead camera (I use that setup at my front & back doors). Sometimes having 1 or 2 obvious cameras is enough to deter a would-be/wannabe criminal out for a quick "smash & grab". A serious criminal "knows" your place; they have observed you, perhaps even taken notes of your movements, "cased" your location at various hours, studied avenues of approach to your doors & windows, and considered potential security methods and possible backup systems you have have. A serious criminal is the most difficult for a homeowner to thwart; sometimes crime is going to happen no matter what you do.
Closing thought. Consider a "layered" approach to home security. A dog combined with a few carefully placed cameras in "motion detection" mode, high quality door locks, solid-core (or wood-appearing steel) doors, and a decent security/burglar alarm covering doors, window breakage and interior movement (motion sensors) makes for a pretty tough defense. Also consider what might be attractive about your house. Nice boat in the driveway or side yard? Big truck in the driveway that doesn't fit in the garage? Lots of CB & ham radio aerials on the house? Lots of nice "fancy stuff" that can be seen through the windows, like a glorious holiday tree in the winter time? Any signs of nobody being home (lawn needs mowing, newspapers not picked up, etc.)? If your "significant other" complains that your "security measures" make the place "look blah" or "unattractive", ask them this: "Would they rather have to replace the nice stuff that people can see on a constant basis, or do they want to retire with a nice nestegg for their golden years?"
Perhaps the easiest way to sum up a security exam of your own property is this: "Think like a criminal."
Yes, you heard something like that on NBC's "The Blacklist" TV show, assuming you watch that.
I used to do networking & network security for a living. Now I just do it for fun, but I still take it seriously.