[ElrodontheV-Rod]

Clutches wear out from being slipped too much. Things like holding the weight of the bike when waiting at an up hill junction. Heat and too much friction. Clutch use should be quick but smooth. Poor adjustment can kill them quickly too! No slipping is the key to long life.

Providing the duty of the clutch remains matched to the power,a clutch should last forever if it's used correctly.Doing a burnout cannot hurt the clutch because it's fully engaged while doing it.It is definitely in the friction zone as to where and when the most wear and tear is made.I've also seen people that don't engage the clutch properly after selecting the next ratio in the trans.I've noticed more riders nowadays do not know how to properly use a clutch.
A good example for life expectancy is the clutch in my old S-10.It has 300,000 miles on the original setup.

 

[ElrodontheV-Rod]

I just replaced my original clutch with a slipper because of peer pressure on this forum. The old original clutch had 80K miles on it. I disassembled it and no signs of wear and tear at all. Could probably get 200K on it no problem. but then I am not an aggressive rider.

Aggressive riding is not what wears a clutch.To much use in the friction zone is the most common way I've seen a clutch wear out.
If my wife drove my little truck,the clutch would be fried in less than 1000 miles.
As long as the clamping force is greater than the torque input,it is virtually impossible to wear a clutch out.