Did you ever wonder how to get informed when Nagios doesn't run anymore?
Just use this line...
OUT=/usr/lib/nagios/plugins/check_nagios -F /var/cache/nagios3/status.dat -e 1 -C nagios3
|| echo $OUT | /usr/bin/mail -s "[NAGIOS] Nagios LogFile STALE" spambox@....com
... called once an hour by Cron and you will at least get informed.