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Moving to an ERP is often postponed because “it still works”. The spreadsheet holds, the accountant knows the traps, the logistics manager knows which figure not to trust. The day one of these people goes on leave, you find out what that “it works” was costing.
In short
Size is not the right criterion; re-keying and gaps are.
Three signs together justify opening the subject.
Measure before deciding: re-keying hours, invoicing errors, close duration.
These measurements are then used to judge the project at 90 days.
The seven signs
1. The same data is entered twice or more
An order typed into the CRM, copied into the invoicing software, then into the picking spreadsheet. Each re-keying takes time and produces errors. It is the first sign, and the easiest to measure.
2. The displayed stock is wrong
When the team counts before promising a lead time, the stock in the system no longer serves any purpose. Lost sales and rush orders to suppliers cost more than people think.
3. The month-end close takes days
Reconciling invoices, receipts and purchases by hand, then waiting for everyone to send their export: if the close goes beyond three or four days, the tool is at fault, not the team.
4. Nobody knows the margin per product or per customer
Without a purchase cost attached to the sale, margin is calculated in a spreadsheet, once a quarter, with assumptions. An ERP calculates it at every sale.
5. The tools do not talk to each other
One tool per department, exports every week, one person acting as the bridge. That human bridge is fragile, and it does not grow with the company.
6. Growth means a new company, warehouse or country
A subsidiary, a second depot, export sales: each multiplies spreadsheets. An ERP manages them in a single database. See Multi-company ERP.
7. A legal obligation is coming
In France, e-invoicing becomes mandatory on the receiving side for all companies from 1 September 2026. Invoicing software that cannot exchange with an approved platform forces the question. We detail the timetable in France’s e-invoicing mandate.
Measure before deciding
Before asking for a quote, take two weeks to measure:
- Re-keying hours
Per week and per department.
- Errors
Credit notes issued, deliveries redone, unseen stock-outs.
- Close duration
For the month, in working days.
- The tools
In place, their annual cost and what they exchange.
These figures do three things. They tell you whether the project is justified. They give the scope of the requirements document. And they serve as the starting point to judge the project’s return at 30 and 90 days.
When it is better to wait
An ERP does not fix a fuzzy process. If every sales rep builds quotes their own way, if discount rules are written nowhere, the ERP will freeze the mess. Better to write the rules first, sometimes with a simple CRM, then move to the ERP. Likewise, a company in the middle of a reorganisation gains by waiting until roles are stable.
The French administration details the e-invoicing timetable: it is often the concrete trigger in 2026.
After the decision
Once the signs are confirmed and the measurements taken, the rest follows known steps: write the scope, choose the tool and hosting, migrate the data, train the teams, open in batches. The complete ERP guide describes them in order, with one article each. If you prefer support from the start, the scoping of our CRM and ERP offer starts from your measurements to tell whether an ERP is really justified, which one, and on what first scope. Sometimes the answer is “not yet”: that is a useful answer too, because it avoids a project launched too early.
Frequently asked questions
Isn’t a well-made spreadsheet enough?
For one person, often. For a team, the spreadsheet breaks on three points: several people editing at once, no history of who changed what, and formulas that drift. When the spreadsheet becomes a critical shared tool, it is the sign you need a database.
Does a services company need an ERP?
Not always. A services company without stock often does well with a CRM, an invoicing tool and time tracking. The ERP is justified when project management, re-invoiced purchases and progress billing become heavy to reconcile.
How much does an ERP cost?
It depends on the scope far more than on the software. For Odoo, our three-year calculation details the four items: licence, hosting, setup and operations. Our Dolibarr and Odoo tiers start at €6,500 and €15,000, on a written scope.
Sources
- E-invoicing, French Ministry of the Economy (new tab)economie.gouv.fr
Jim · founder of Brain Plus AI
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