Large edging contract, question

Ok, may seem obvious from the title, but a new property I am likely taking on wants almost 2 miles of sidewalk and curbs edged, They have always been maintained 3 times per year so they are not overgrown. One of the board members specifically requested a walk behind style edger not a handheld tool. He believes it looks better and keeps longer. At what they are paying for that and other services Im not going to argue. My questions are

1. What times of year should I plan on edging them. I...

Large edging contract, question