Free solo climbing -- climbing without the use of ropes for protection -- is a no-margin-for-error hobby. That's not the style of ascent being done by Caldwell and Jorgeson here though (it would essentially be suicide!).
Free climbing (climbing without the aid of a rope but using it for protection in the event of a fall) is a quite forgiving hobby! I've fallen hundreds of times while free climbing and lived to tell the tale :).
The distinction between free solo climbing and free climbing is frequently a point of confusion -- especially in news articles!
Modern equipment has taken us a long ways from "the leader must not fall" but how forgiving a leader fall will be is still highly dependent on the route. For instance The Bachar Yerian [1] in Tuolumne Meadows (the Yosemite high country).
These guys are falling a lot on their way up. Don’t they want to climb the whole thing without falling?
Well, that would be nice, but in this case, it’s okay for them to fall. They’re trying to “redpoint” the route, which means each climber has to climb each pitch without falling. So, if Caldwell is climbing pitch #11, and he falls 40 feet from the start of the pitch, he lowers down to the start of the pitch and starts over until he finishes the pitch cleanly. Then that pitch is considered free climbed, and he moves onto the next pitch. Since each pitch can take a half hour to an hour to climb, you can imagine how ridiculous it would be to climb all the way up to, say, Pitch #17, and if you fell, lowering 1,700 feet to the ground and starting over.
Probably worth clarifying: each pitch is being climbed in order, and for each pitch alone they not using ropes to ascend. But between these harder pitches (at least, and maybe all), they return to a base camp (on the cliff-face) before using ropes to ascend up to where they want to start the next pitch.
