Originally Posted by Al1943

I've used cadence on all bikes for 12 years and would not be without it. For the same reason all of my motor vehicles have tachometers. I want to know how the engine is doing. Similar to a car's engine cyclists have a cadence (rpm) range where we are more efficient. Testing has shown that to be approximately 85 to 110 rpm. I have found cadence to be especially helpful when I'm pushing myself on a long ride and my body is tired. If things just don't feel right I check the cadence and if it's sagging I'll find a gear combination that lets me get the rpm back where it should be. This often improves my condition and the speed will start creeping back up. This is especially true when fighting a headwind.
When my wife took up road cycling she had no experience with multiple gears. Her cadence meter helped tremendously with learning gear selections. She's quite small and is able to offset a torque shortage with a higher cadence. Now she cruises at 100 - 120 rpm for hours. Not bad for a 63 year old.
I think the most reliable computer with cadence is the Cateye Astrale.

Al