How do I know when I need a new clutch?

[70Sixter]

Slippage is detected first in low gears when the tach goes up faster than the speed you are headed for. As it wears further it will slip in the higher gears. Eventually you'll be able to rev the engine in top gear with no acceleration.

Replace all the clutch components when you open it up. You don't want to have to go back in to replace the throw-out bearing later.