The dog days of summer can be a killer for Pennsylvania lawns. Going for extended periods without water, your lawn decides it's better off to just take a nap than to try grow and stay green. Trying to keep up with occasional watering with a hose and sprinkler can actually do more harm than good; your lawn is tricked into thinking it's OK to put effort into growth, but it's health is undercut when you forget to water for a few days.
The rest of your landscape plants can have other issues in other season, too. An irrigation system can ensure that your plants and turf receive the water they so need. And with on-site rain sensors, your irrigation system knows if there's been adequate rainfall to not need additional watering and simply remains inactive until the next scheduled watering.
When you consider the money you'd save in replacement of your investment in trees and shrubs, and the cost of water lost to the sewer system using the wasteful hose-and-sprinkler method, the time you'll save will be an added bonus. You'll also have some of the healthiest plants in your Pennsylvania neighborhood. Bragging rights are worth something, too.