Dethatching and aeration is a great way to help your lawn to grow it's best. While doing both of them in the spring and the fall every year may seem excessive, it is in fact a great way to help your lawn prosper and look great. Dethatching and aerating in the spring removes dead grass from the winter and relieves compaction from the snow, from walking on the grass, and from it not being watered over the winter. This will help your lawn come out of it's winter dormancy strong, grow well and look great. Doing a dethatching and aeration again in the fall will remove any thatch build up from over the summer and relieve compaction from walking on the grass, mowing it, and the dryness of summer. This will help the grass to go into dormancy strong, so that when the weather breaks in the spring, it is ready to grow. Doing this every year sets your lawn up to grow and look it's best all season, every season.