I have a 35' cord and a 15' extension. To date, I've never used the extension. But its one of those things that when you need it, YOU NEED IT. But more than likely, the best use it serves is to give you a little more flexibility as to your setup on some sites. For example, one of the places we visited this summer required us to stretch our our entire main cord to reach the pedestal because of where we wanted to setup. And our plug is on the back corner of our rig. If the plug was another 2-3 feet forward, we would have had to use the extension. But if the extension was available, we would have had to park further back and the setup would have been far less ideal.