Originally Posted by LesterOfPuppets

Once a year or so, take a nice flat blade spade and dig out a wedge 1-1.5" wide at the top all along the sidewalks/driveways. It's a lot of work initially but if you're doing weekly line-trimming it's a lot easier when there's a gap. Probably not good in frequent freeze areas, as water is more likely to get under the concrete, freeze, then heave.