I always like to think of the lawn like a human body. Eat your veggies, get lots of exercise, take your vitamins, take medicines when you get sick and so on and you will likely lead a long healthy life. Spend your life drinking, smoking, and doing drugs and your body will probably pay for it. A well cared for lawn should be expected to last anywhere from 30 to 40 years. Most lawns will likely start to show their age at about 25 years and will likely need to be “renovated” at least once or twice by adding a few layers of soil, seed, and by aerating annually in order to extend its life.