Piety Corner keeps its own hours — porch lights still burning, a dog barking two streets over, the first mower of the day warming up at the curb. That is where A. Bonadio & Sons Landscaping likes to begin: mowing, trimming and edging until a Waltham lawn holds a clean line all the way to the sidewalk. Come winter the same driveways get plowed and salted before the coffee finishes brewing, so nobody in the house has to fight their way out to the street. There is a plain pleasure in a stripe cut straight and a walk scraped down to pavement. Waltham and the towns around it get both halves of the year from the same crew.