Your reports disagree with each other, and someone reconciles them by hand.

• Two reports give two numbers for the same week, and both of them are "right".
• Month-end is someone exporting from three systems and reconciling them in a spreadsheet.
• The POS says one thing and QuickBooks says another, and nobody can say which is wrong.
• A vendor shows up as an ID with no name, so nobody can answer "what did we pay them in period 8?"
• Opening a new location means a week of someone editing reports.

The schema your reporting should have been sitting on. Reference tables for the things the business actually has (locations, roles, vendors, accounts) instead of mappings copied into every report. Real types, so a date is a date. Foreign keys that hold, so a row that doesn't match anything is caught on the way in rather than quietly dropping out of a total.

Then the ingest. Each feed gets fixed once, where it enters, instead of every report patching it on every read. Reporting is rebuilt on top and runs next to the old reports until the numbers agree. When they don't, you find out which one was wrong and why, and it's usually the old one.

What changes: month-end stops being a reconciliation project, and a new location is a row in a table.

One boundary worth setting early: a rebuild can only be as complete as the feeds behind it. If a system doesn't send something, like bill-level detail or the rate for a salaried shift, the rebuild says so plainly rather than filling the gap with a zero.

PostgreSQL or MySQL, whichever you already run. SQL models, versioned and reviewed like any other code. Nightly feeds from the systems you already pay for: point of sale, payroll, accounting, scheduling, reservations. Your existing BI tool, pointed at tables it can actually trust.

If the business runs on one tool and its built-in reports are enough, you don't need this. Keep the tool.