So yesterday I'm in a little pickup group. Three riders came by going 1mph faster than me and asked me in. Not used to seeing that sort of sociability amongst new riders. And they were riding clean so I got on. We did about 6 miles together. It was dead flat, all with a small tailwind square behind us. At the end of the section they told me (no computer on my bike, not realistic at all on a 1960 bike) it had been mostly 24-28mph. They all had latest and greatest derailleurs. Those things are fast and precise. Two of them were making these sharp clicks when they shifted and the other one sounded like a small caliber pistol. It was resonating a lot on the deep dish carbon rim. In six miles I would guess each of them shifted 50 to 100 times. If you need to do that sure it helps to have a derailleur that shifts in one thousandth of a second. I didn't touch my shift lever once. No need.

Rolling hills the superfast new derailleurs could be useful. Also helps to have the ability to push and the ability to spin. Legs that can do more than one thing. Legs not tech.