It is hard to tell. To be honest when spring arrived my grass couldn't have been thicker or greener. I definately attributed the aeration to the new and improved lawn. However, when the hot summer drought hit us, i was dissappointed. Alot of what appeared to be thatch, or brown lifeless grass. A few weeks ago, I laid the nitrogen heavy fertilizer down right before a week's worth of rain. The rain, accompanied by the cooler weather, brought that lifeless grass back to attention. I mowed last night and wouldn't want my lawn any thicker without having a bagger.
I would say the aeration probably had alot to do with it. i won't do it yearly, but will probably aerate every other year. Next time, I will pull longer plugs.
I have to tell you, my lawn is three years old and i really never thought it would look this good this fast. I want to give honorable mention to "Menards" home improvement store. Their sales prices, along with the additional rebates, on their brand fertilizers have made it possible for me to keep my lawn feeding on a regular schedule. With their latest sale, I was able to winterize my lawn (1 acre) for $36.00! Will post pics soon.
Grasshopper it has been 1 year. Did your efforts pay off?