I think the call before you dig is about liability. If you know where stuff is and you are 500 ft away, it doesn't matter. In my experience it isn't that useful. They don't mark my underground power, water or coax, only the utilities' main lines. They never mark the fiber, though there are 3 ft high fiberglass posts to mark the general area. All our utilities are in the front 50 ft of the land, the back 10 acres have nothing. I call when I'm digging up front but am constantly doing something in the back and not calling.