get the mower out too often. unfortunately this is the worst thing you can do as it leaves the roots with little protection from the hot summer sun as the soil will dry out faster. for more on lawn and garden care, click here.
deep watering once or twice a week, depending where you live, is so much better as it encourages the roots to go deeper into the soil so when the top layers of the soil dry out they will be able to survive much better until the next watering.
as a general rule of thumb, no more than one third of the blade of grass should be cut off, 