We close up the house, and turn off the water when we are going to be gone for several months. The local police will check on the house regularly and we have a neighbor who cuts the grass. In addition I have security cameras that not only record everything all around the perimeter of the house and inside but are also accessible through the internet for us to get a "real time" idea of what is going on. If we are going to be gone during hurricane season, we make sure that the window protection is already installed.
One year we notified the newspaper to stop delivery while we were gone. One of the neighbors noticed someone around our house at 4AM and called the police, who found our newspaper delivery man wandering around in the back yard. He said he was trying to find a place to fish, since we live on a lake. He no longer works for the newspaper. :R