Half Ropes?

Two additional reasons for using half ropes trad climbing (even at the crag):

1. It provides a "fresh" strand if the top piece blows during a fall. If a piece fails while using a single, the rope won't have time to regain its dynamic properties before it takes on the next piece, greatly increasing the force on the next piece and the chance of that ripping as well.

2. If you have two suboptimal placements close to each other, half ropes gives you an easy and effective way of equalizing them, by clipping one strand to each.