Your lawn will always benefit from aeration and overseeding, Lawn aeration penetrates the soil by removing a soil core which allows for less compaction, and allows more oxygen to the root system of the grass plant.
Aeration will invigorate roots and stimulate new growth, reducing soil compaction and thatch accumulation. Overseeding grass seed after aeration will encourage new growth for a thicker lawn. Annual aeration and overseeding is great for promoting the health and appearance of your lawn.