I introduced Nagios to an organisation in 2004 to track the availability of various servers and network resources. It has since grown into a system validity tool that takes the stress out of help desk. Using Python as a scripting language, I have created a suite of additional Nagios plugins that ensures: * real-time entry of market rates * end of day rate integrity * common errors in manual spreadsheets * success of backup processes * validity conditions in MS SQL databases * routine tracking of known chronic errors