Is it inadvisable to leave a permanent knot in ones rope for the purposes of rigging? A few above ground rappellers I know leave a permanent fig. 8 in their rope end, flop it around a tree or whatnot, and simply clip a carabiner through the knot and around the rope.
Also, several sources, including "On Rope" suggest alternating the ends of the rope when rigging. I wonder if rope length would sometimes make such a practice unwise. I for example have ropes of two lengths; two 60m and two 45ft. (obviously I don't do any major vertical caving). If I have a 50' pit I have to use a 60m rope. If I alternate ends I will wear both ends of a rope that I usually only use maybe one third of. Would it not be better to use the same end and preserve the rest of the rope? Since I don't usually need long rope I could chop off the worn end eventually and still have 40m of practically unused rope. Or am I overcomplicating an obvious situation?