[FrostKiwi]

The commenter was referring to having compilation and linking in separate stages, as is standard in Makefiles to enable Multi-Threaded compilation. As in

  cc -c main.c -o main.o
  cc -c init.c -o init.o
  cc init.o main.o -o final_binary

In that specific setup, ccache does indeed not provide a speedup, since those .o file are kept. The Makefile simply checks if the source file has a younger modification date than the object file and recompiles only if it's older. In that sense the Makefile does in fact cache the results. Once we go beyond single-user and onward to bigger projects, ccache starts making sense.

[slavik81]

All rules inherently depend on the Makefile they are defined in. The second you touch the Makefile rules, you have potentially invalidated all the object files. So, ccache is great when working on the build rules.

Using ccache is also nice when you have generated files. If you edit the generator code but the output is identical, Make will needlessly rebuild everything and ccache will make it quick.

[Jorengarenar]

Unless you `make clean` as creators of ccache notice on the linked site