to lead on a single half rope?
on alpine climbs I've done this before on stuff I know I won't fall on, like 5.7. it's a 8.6 50M.
how hard is it to break a rope? this weekend I'm going in to do the serpintine arete. I don't want to carry 2 ropes for the 4-5 pitches that are 5.5 or so, becasue I don't want to carry them on the upper 4th class.
on loose 4th class often I'll put the rope away, if my partner is comfortable with it. the reason, it's safer. the rope can catch loose blocks and bring them down onto it self and me. the closest I've come to being hit by rockfall was being roped up on loose 4th class terrain. the rock missed me by a couple feet and then nailed the rope, almost cutting it in half. I didn't notice the core shot until halfway down a rap!