When I started out riding I used to push gears that were way way to big, not keeping a high cadence as a result. I though this was the best way because of my build. When I started doing rides over long distances with 20 or so mile hills, I found it so much easier to spin at 90-100 r.p.m.'s especially on hills. But once again this is a personal preference, I know people that spin at all different rates, the fad now is to spin, but like I said before just find what works for you. You aren't getting graded on your technique, you only grade yourself on your enjoyment.