Since I changed to compact bars I've spent a lot more time in the drops...maybe up to 30-40% of a ride. One thing I noticed when I first started riding in the drops was that I'd work harder and had to learn to measure out my effort better. The thing that is my limiting factor in the drops is my neck gets tired holding up my melon. I try to look through the tops of my glasses and keep my head more down but that doesn't work so well in less familiar areas where I feel like I need to be a little more alert.