Core aeration can help make your lawn healthier & reduce its maintenance requirements through these means:
Compact soil prevents grass from establishing a healthy root system & keeps water & fertilizer from reaching the roots. Walking, playing & mowing will compact soil & stress lawns. Raindrops & irrigation further compact the soil, reducing large air spaces where roots readily grow. Compaction is greater on heavy clay soils than on sandy soils, & it is greatest in the upper 1 to 1 1/2 inches of soil. Aeration can help relieve soil compaction, allowing your grass to grow deeper roots & make better use of water & fertilizer.