I've had several types of security cameras over the years, in our last home and in our present house.
I currently have a 8 channel DVR (digital Video Recording) Surveillance system. The 8 channels allows me to hook up 8 cameras in different areas around the house. Like some of the others mentioned it connects to the internet and allows you to view your cameras live or review video clips that the motion detection feature captured. The internet connection is great if you are away from home much. Our family was in another country for a couple months last winter, yet I was able to check my house just about every day and could tell if anybody had been there, when, and for how long. I even averted a possible problem when I noticed the snow piling up and starting to cover my outdoor heat pump unit, so I emailed a couple friends in the neighborhood and they quickly took care of the problem for me. I even watched them shoveling the snow.
Video clips are recorded to a 500 GB hard drive that holds about 3-6 months of videos. Videos are recorded anytime the cameras see something moving within their field of view. People, cat, spiders, tree branches moving in the wind, even cloud shadows can sometimes set off the motion detect so it starts recording. So you can sometimes get a lot of recorded video clips. You can adjust the sensitivity of the motion detection and make it less sensitive, but I like to keep mine fairy sensitive to make sure I catch everything.The only problem with having to many videos might be it will fill up your hard drive faster, but when that happens it just starts writing over the oldest videos. Videos are recorded by camera channel and time, so it's easy to find and review a specific video event if you have some idea what you are looking for.
What do you plan to use yours for Lou?