Originally Posted by crassius
a lot of variation on that due mostly to how the rider uses the clutch
usually last about a year with careful riding, but I've seen them wear out in a few months (usually less than $10 for new pads tho)
I have three bikes with well over a thousand miles on the original clutch friction pads. Riding style will have a lot to do with the longevity of the pads. If you like to try motorcycle starts from a dead stop and 'slip' the clutch a lot, naturally that will shorten their life span but pedaling up to speed, about 10mph before engaging the clutch will make them last much longer.
I'm sure that pad quality plays into it too. I've been fortunate and had good luck with my engines but as Crassius said, there have been reports of premature pad wear from some members.