There are many advantages to getting a timed lawn sprinkler system if you have a big lawn over watering your lawn yourself with a garden hose. 
First off, grass lawns have very shallow root systems that can't hold a lot of water. When you water with a garden hose, most of the water just runs away into the street, down the drain and into the municipal water supply. For this reason, please don’t use a lot of chemicals on your lawn today, as you could wind up drinking it tomorrow.
Convenience
Watering your lawn is one of the worst wastes of your time – if you are not into watering your lawn. You'll also get a lot of strange looks from people, especially if they've been woken up early on a weekend morning by you mowing your lawn. A timed lawn sprinkler system is one of the quietest and convenient ways of getting two things done at one – watering the lawn and doing whatever you need to do besides watering the stupid lawn.
