Are there any files created and or broadened by the system besides mail and logs? Are there any files created and or broadened by the system besides mail and logs? AFAIK, the only files that are created and/or broadened by the system in default are `/var/mail/` files and `/var/log/` files (broadened by means of file size). To cope with that I've redirected `/dev/null on files in these directories. But are there more files besides mail and logs that I should worry that they'll be created and broadened by the Linux system itself, throughout time?

I'd recommend reading up on the Unix filesystem.

The `/var/` directory holds frequently changing files. The `/etc/` directory holds configurations that don't typically grow too much. the `/usr/` directory holds OS files that don't change too much outside of system upgrades. If you have third-party applications running off of `/srv/` or `/opt/`, those directories may grow.