A Haverhill Saturday in July starts with the sound of mowers going up one street and down the next, past back yards no bigger than a room. www.littlemowershop.com works those pocket lots and the wide ones alike: mowing, edging along the walk, trimming into the fence corners, mulch in the beds, spring and fall cleanups, leaves gathered before they mat down over the winter. A little yard done carefully looks better than a big one done fast, and that's the whole approach. By noon the clippings are up, the borders are sharp, and the lines still show from the porch. Haverhill and the towns close by.