The clutch automatically adjusts itself so you don't have to worry about it.
As far as wearing out, as the clutch disc wears/thins, the pedal has to travel further out before the disc catches the flywheel.
To help with how the clutch works, here's a great article with animated illustrations of what happens inside the clutch assembly
http://auto.howstuffworks.com/clutch1.htm
There are a couple of differences in your clutch from the one that's in the illustration. When you get to the exploded view of the clutch assembly, the clutch disc (plate) in their illustration has the central shaft attached, but in reality it is separate from the clutch disc. The disc slides back and forth on the shaft when the clutch is engaged so it can't be attached. Next, , it shows a pressure plate and diaphram spring. That's one fused unit rather than two separate parts in Porsches. The other thing is the release fork shown in the illustration is a heavier arm that's mounted vertically in Porsches.