After some time your lawn will develop thatch, a layer of useless or decaying grass leaves, stems, and plant roots which actually are found under the green vegetation of your garden. All thatch is not really necessarily a bad thing and in fact small amounts (less than 1/2 inch) are actually good for the yard. A good amount of thatch is going to help your grass resiliency, strengthen tolerance against traffic, and protect against extreme soil temperature switches. However, if the thatch layer begins to go beyond 1/2 inch, issues will come about like your grass actually expanding in the thatch layer which affects its strength and hardiness. Additionally, problems such as localized dry spots, mower scalping, disease and even bugs can become part of the situation.