danthecavingman said:
Just because you're down a familar dig and "It's quicker without a lifeline" doesn't mean you won't get hurt if you fall.
I know someone who took a tumble down Garlands Pot in Giants when the natural eyehole he had his wire belay round broke.
I've known him for over 20 years and it's the only occassion that I can remember him not using a lifeline. Luckily there was another ladder down the pitch for him to use to get out. Many of us don't treat little, well known pitches like Garlands with the same respect as larger, more obscure ones. Remember that if you are unlucky you could break an ankle from a 6" fall.
Getting back to the subject:
I've always been told, and always taught others, to leave your ladder rolled at the top of the pitch and to rig your lifeline. Thereby using their ladder to climb on, but using your known rope to lifeline with. If it is unfeasable to place two lifelines down the pitch then remove the existing one before replacing it with yours (only one person from the other group then has to use your rope to climb the pitch, and they can then replace your rope with theirs for the other members of their group) And when removing your gear from a pitch head, replace it with gear left by other groups.
It all gets much more complicated if there is an SRT rope being used for self-life lining on a ladder pitch (in which case it must be left for the other group to use) or a group has used SRT spaghetti over all the available belay points (the last time I saw this was on a pitch less than 20'; we left the cave and waited for the DCRO call-out. There was no safe way we could rig the pitch without entanglement in their spaghetti! :x The group were obviously lucky that day as there was no call out.)