East of town the ground tips toward the East Branch of the DuPage River, and on a July evening the fireflies come up out of that low grass by the thousand. RIO Land Care Services works the lawns on the way there — weekly mowing, trimming along beds and posts, edging that holds a straight line down the drive. Summer here is humid and fast, and a week is exactly as long as a lawn can be left alone. Fall slows things down and turns the work to cleanup, clearing leaves off the turf before they mat down for winter. The finish is what stays with you: cut, edged, blown clean, nothing left to do but look at it.