tldp.org quotes /var as:Files in /var/log can often grow indefinitely, and may require  cleaning at regular intervals.So without cleaning, using a system for a long enough period will fill up all of /var.Do some distros rotate logs automatically or is in generally accepted it's the user's role. With so many new people getting into *nix, this be better know, and how should this be handled?
Does /var keep growing in size?
logs;disk usage;logrotate;var
There is logrotate which cleans /var/log regularly by using cron jobs.It is normally installed automatically (at least in Debian and its derivatives  like Ubuntu).