The workbook that runs the business.
Every growing company has one. It works, it is fast, and it is held together by one person's memory of which columns must not be sorted. The problem is not the spreadsheet. The problem is that it cannot be handed over, audited, or used by two people at once.
Four jobs in one file.
A business-critical workbook is usually doing four separate things at once, which is why replacing it feels harder than it should. Separate them and each one has an obvious home.
Holding records
Customers, products, jobs, stock. This becomes proper data in Odoo, with one record per thing and no copy-paste drift.
Calculating
Margins, lead times, reorder points, quoted prices. The formulas are the valuable part of the file and usually become configuration or a small custom module.
Running a workflow
The colour coding is a status field. The tab order is a process. This is the part a spreadsheet does worst and Odoo does best.
Reporting
The pivot someone rebuilds every month. Once the data is in one place this is a saved view, and it is live rather than a snapshot.
Send the real file, not a cleaned copy.
The inconsistencies are the most useful thing in it. Every exception someone has typed into a cell is a rule the business actually follows.
Read it with the person who maintains it
Half a day. They explain the columns, the hidden sheets and the rules that never got written down.
Separate the four jobs
Records, calculations, workflow, reporting — each mapped to configuration, a module, or a view.
Clean on the way in, once
Deduplicate, standardise units and codes, and decide what is dead. This is the only free chance to do it.
Run both for a fortnight
The workbook stays open until the same question gets the same answer from Odoo. Then it closes for good.
What should stay a spreadsheet.
Not everything belongs in a system. Modelling, one-off analysis, a scenario you are arguing about with your accountant — those are spreadsheet work and always will be. What should not be a spreadsheet is anything two people need to edit, anything that must be auditable, and anything the business cannot trade without.
Odoo exports cleanly, so the modelling can carry on in Excel with live data underneath it instead of a stale paste.