In reply to Ridge:
im with iain - carrying just in case, nah. but using 2 to actually cover steep ground with works well.
i run with two a) when its steep, b) when theres bouldery rivers to cross and c) because im a sissy - but a sissy with good knees.
if youre going to start carrying anything, then 1m of wide sports tape to support the ankle, applied as soon as you realize youve done damage, apparently makes a difference. gaffers tape also works, but the roll is larger and the decent stuff costs more than sports tape.
another option is to equip your dog with a little pack, so he can carry them for you. in which case throw in a tarp, thermarest, fire making implements and some stock cubes. if benighted you will be well equipped - with a food source that carries itself.