Pro's used to ride with a cadence between 90-95 RPM.
Untill an American guy, coming back after a serious disease started to work on his first comeback with a lighter gear and higher cadence (because he was to weak to use the heavy gear) dicovered that he could produce a higher powerage (he had and still has a perfect body for the sport).
From that day, every cyclist hopes that he can bike with a cadence of 115 RPM or even higher....
We all know what happened with the american guy (7 TDF victories).
Whats the lesson: use a cadence that's com comfortably and try to train it to a higher level.
As for myself: I started 2 years ago to train my cadence at 90 RPM and now I'm very happy with an everage of 98 on a flat ride. In the Alps I used to ride at 55-65 RPM and now I'm at 70-75 (wich feels better). Sadly enough, I'm not goin faster...(but that could be the age)