I think just riding the clutch is worse then power shifting. In other words, sitting on a slight incline and using the clutch to hold your position rather then using the brakes. Or letting out the clutch TOO slowly in first from a dead stop while revving the engine up excessively.
My Z has around 63K miles or so on it and I am assuming it is the original clutch in there. With the number of miles on it when I bought it, I think it's safe to assume that most of the miles were highway miles, which would be much easier on the clutch then city miles.
When I had my headers installed the tech warned me to go easy on the clutch because the headers will increase the cost in replacing it. He indicated riding the clutch is the worst thing anyone could do. As long as your tires will break loose if you dump the clutch, then the wear and tear on the clutch isn't all that bad if it is driven that way. But if you have sticky tires that grab real well, then the clutch becomes the next component in line as the weak link....
Good luck!
__________________
|