Rumor has it that somebody should be fired at Google Germany, because he or she forgot to renew Google’s domain name. Apparently, when you go to google.de (from a German location) you get a parked host site.
Let that be a lesson to you and put in place an ironclad policy regarding your most important web asset. This policy could contain not only notifiers about renewal action, but also regular action to monitor who out there is registering confusingly similar domain names or is doing other kinds of mischief. Monitor compliance with the policy.