Last week, a colleague of mine was told by a senior IT member at one of our major clients (an international company) that our bespoke software was used by more users that their 'core' SAP system; when asked which of the two systems were of the most value, he would not say!
Bespoke software applications fall into several categories, in this case, the package in question is a KPI (key performance indicator) setting and monitoring tool which takes input from amongst others, SAP. It's use is scaleable across the organisation from team leaders managing small groups right up to board members looking at the 'bigger picture'
So what is your 'core system'? - not a series of Excel spreadsheets I hope!