It is okay for a clutch to wear over time. Even under normal conditions, the engaging and disengaging of the clutch from the engine wears the clutch friction disc. However, there's no straightforward answer to how long a clutch will last. You might have seen some folks who wear their clutch under 30,000 miles. On the other hand, you can also see someone who has covered 100,000 miles with a clutch, and it's still working fine.