If you’re on Fedora 11 (conceivably earlier too, I regretfully haven’t regularly used Fedora since Fedora 6, until recently), the basic developer tools package combo includes ccache, and caching Just Works in Firefox builds with no extra work needed at all.

[jwalden@the-great-waldo-search dbg]$ \
> ls -la `which g++` `which c++` `which gcc` /usr/bin/ccache
-rwxr-xr-x. 1 root root 43584 2009-02-23 23:42 /usr/bin/ccache
lrwxrwxrwx. 1 root root    16 2009-10-02 21:29 /usr/lib64/ccache/c++ -> ../../bin/ccache
lrwxrwxrwx. 1 root root    16 2009-10-02 21:29 /usr/lib64/ccache/g++ -> ../../bin/ccache
lrwxrwxrwx. 1 root root    16 2009-10-02 21:29 /usr/lib64/ccache/gcc -> ../../bin/ccache
[jwalden@the-great-waldo-search dbg]$ du -hs ~/.ccache
883M	/home/jwalden/.ccache

Anyway, use whichever distro you want, with ccache or without, whatever satisfies your preferences and utility curve. (The semi-troll title is completely gratuitous, but my sense of humor mandated I use it. ) As for me: I am an absolute sucker for convenience. I’ve known of ccache for years and never used it before due to the activation energy needed to do so; had using ccache required equivalent effort in Fedora I strongly doubt I’d ever have used it. Score one for making the right choice for the user rather than requiring him to make it himself.