It's never been easier to set up your own home security system. However, if your cameras can record audio, depending on the state or territory you live in, you could run afoul of privacy laws if you don't have consent from people who visit your home.
As product review site The Wirecutter points out, setting up cameras to keep an eye on your home is perfectly fine. Recording, on the other hand, can introduce some legal complications. Especially if you record audio in a state that requires dual consent.
Video and audio recordings have different legal guidelines and there are worlds of nuance to navigate. For example, you'd obviously be allowed to watch a live feed of your front door, but if you put a camera in your bathroom and recorded your guests, you'd up in legal trouble even if it's technically on your property. Laws vary slightly from state to state, so you'll have to check your local laws for specifics, but it's worth doing before you set up your security system.