Most lawns will benefit from regular aeration, however, lawns that get heavy use (compacting the dirt), were initially established as part of new construction (with minimal top soil), or lawns that were initially created using sod (multiple layers of dirt), tend to benefit most from aeration. Also, the best time to aerate is when lawn is growing and can recover from the aeration removal of dirt plugs.

You can mow your grass 1/2 inch shorter than normal.