I really like the guidelines - - I'm a fan of "hike your own hike" but something along these lines should be the "standard" to which thru-hikers gauge their hikes. "hike your own hike, yes" but if you want to call yourself a "thru-hiker" something pretty close to this needs to have been attained (not the mileage, mind you, just the standards). That said, I do have an exception though - - I think that hitch-hiking is a viable, time-tested, and resourceful way to get in and out of towns for re-supply thus avoiding long road walks - - I usually set out to walk to town but sometimes stick my thumb out or am sometimes offered a ride at a trailhead. My thinking here is that if you are hitching, you get your ride by your own wits and it's free (unless you give the driver a dollar or two for gas to be nice) - - this aside, I like the guidelines. I also think a 37 mpd average is quite reasonable for a serious and dedicated hiker that really has (and keeps) their trail legs. This seems like a lot of miles to your average 10 miler per day weekender (just like a sub 3 hour marathon seems completely out of reach to someone that runs a 5K every couple of months) but for someone immersed deeply in the trail, absolutely marathon-runner-fit and who that enjoys waking early and moving steadily all day long at a good clip. The normal day would be 40-41 miles - - this builds in a little time off - - it's really quite attainable.