but if the gear is a quest reward for completing the instance, then that's also a different story. i wouldnt run instances for gear either. if it drops, it drops. if not, get the quest reward and move on. =]
Partly because I'm struggling with bosses in the first two instances, this has been my approach. The quest instance quest gear has been a HUGE boost to the defensive ability of my paladin. Worth it right there. However, farming for gear? Wouldn't make any sense to me. Farming rested exp, breaking up questing boredom.... fine.