Core Aeration - What you Need to Know.
This procedure pulls out cores of soil from the lawn to help with compaction and help grass roots receive water, nutrients, air more efficiently. In return, this can help green up the lawn and provide for stronger roots.
We usually advise to do it at least once a year because of the clay becoming so compacted overtime, it's hard for the nutrients to get down to the roots efficiently.
If you want to rent your own aerator, you can rent one from Home Depot or any tool store. They have the gas powered push aerators and the tow behind aerators that you can attach to a riding lawn or zero turn mower.