Why duplication is expensive
Every duplicate creates an obligation to keep it current. That obligation is invisible until two versions disagree, at which point somebody spends an afternoon deciding which one is real — and the customer waits.
How to tell whether you have one
- Changing a phone number once updates it everywhere.
- Nobody asks 'which sheet has the latest version?'
- Reporting is not reconciled by hand each month.
- Two departments quoting the same job quote the same number.
Views are fine — copies are not
A dashboard, an export or a mobile screen showing the same underlying record is a view. A separate spreadsheet someone maintains alongside it is a copy. Views scale; copies rot.