It seems that there's no pattern to clutch wear and ultimate replacement.
Much like driving style is, in my opinion, the single biggest factory to influence fuel usage; I also think that driving style or driving technique plays the biggest part in clutch life or wear.
Put simply, the clutch friction parts cannot wear it it's fully engaged or fully disengaged.
If clutch slip occurs, whether as a result of bad adjustment, bad driving habits, or simply too much engine torque (where it slips even if your left foot is under the driver's seat) then the wear rate is massively accelerated.
Clearly if your engine is dishing up more torque than the clutch can handle then you need to uprate the clutch assembly.
Yet, so many drivers seem to be poised ready to depress the clutch pedal at a moment's notice.
If you practise, and thereafter practice, precise accelerator pedal inputs you might well find you're using the clutch far less. This can only be a good thing for clutch wear and longevity.