I'm seeing compact doubles with 40T cassettes being used by 65 y.o. relatively strong singles riders, not even touring, just to climb at a good cadence. At 76, my low gear is 26 X 30. I think that's a lot better than 34 X 40. That's the same bike on which I used a 30 X 25 at 55. It's a good stiff carbon bike, same frame Lance won his first TDF on, 18.5 lbs. all up.