I have found that a leader longer than 4 feet is a real pain in the butt to cast. I generally use about 3 feet, maybe a tad more, when the water is very clear, but will shorten up to 18-24 inches with off color water. My thought process is that the longer the leader, the longer it takes me to realize I have a strike, and therefore longer for Mr Steelhead to spit out my offering.