There is a covered bridge tucked away in Andover that most people drive past without noticing, and that is a fair description of lawn work done well. O'Hagan's mows, trims and edges the yards around the village and the back roads beyond it, week in and week out, from the first cut of May to the last of October. The spring cleanup lifts off the winter mat so the ground can breathe; the fall one clears the leaves before the first hard freeze pins them down. September turns the light gold by four in the afternoon here, and a fresh-cut lawn under those maples is worth stopping for. Nobody notices the effort — only the result, which is rather the idea.