I've replaced 3 clutches now. Highest mileage was at 11k and lowest was at 2.5k
Eek! Not got figures for two and three speeder clutches but ought to be way more than that. I've changed the thrust bearing (carbon) but I wrecked the old one, and can't blame the car! I put the same driven plate back to get more use as well.
Two people can do a clutch plate replace on a two and three speeder in as little as 20 minutes. No need to replace driven plate as a rule.