The length I quoted would be from where my feet are at (next to a marker on the lawn) and the tip of the leader. I seldom have to cast that far to catch a fish and when I have hooked up at such a distance it is a dice shoot as to whether I'll land the fish.
With bigger rods and lines fishing for salmon and large trout I have a phobia about hooking fish on long casts. I've had fish grab a fly at 40 feet and before you know it have turned down river pulling the entire 120 foot line with and are deep into the backing. If this were to happen at a distance of 100' as a starting point I figure I would have had that fly line and backing broke off my reel years ago.
I do my best to keep things short & manageable, I only offered the original answer because you ask