The creaking / clicking noise you hear is the diaphragm spring fingers sliding over the contact face of the release bearing when the clutch is depressed. The diaphragm fingers move in an arc, the release bearing just straight in and out, hence the shallow wear groove on the fingers of a worn clutch cover. Eventually it will let go of course, but they can make that noise for many thousands of miles without anything other than an annoying noise.
The fulcrum pin that Matt describes will result in a completely non-working clutch if it drops out. Been there.... It is actually possible to use the cap-headed pin to push out the old fulcrum pin from above, meaning no dismantling required to fit it, then no more danger of it falling out!
Vindicator Sprint, Honda Fireblade RRX 919cc, re-powered by AB Performance. Quick.
1995 Trusty Peugeot 306 XND, no turbine, 227K miles young.
1997 Trusty Peugeot 306 GLX TD, 90K miles and soon to ride again..
Alfa Romeo 147 1.9 JTD 150 Ti Lusso , no longer smoking.
Various other transient runners for selling.