What is usually replaced when someone says "clutch needs to be replaced"? on 1998 Volkswagen Passat

A mechanic says the clutch is going to go or needs replacement--is this the assembly, or more parts?

Asked by for the 1998 Volkswagen Passat
The clutch should be replaced as an assembly (pressure plate,disc,throwout bearing) and its a good idea to buy the best quality parts available so it will last for years