Go-live day is not the end of the project. It is the start of the period when the team decides, often without saying so, whether Odoo becomes the system of record or stays one more piece of software next to the Excel file. A few habits in the first thirty days make the difference, and most of them need no technical skill.
Here is a week-by-week plan for a Belgian small business that has just switched over. If the data migration isn't quite finished, start with the data to clean up before go-live.
Week 1: find the Excel files that are still alive
Running the old system alongside for a while is normal, and Odoo's accounting documentation recommends it when switching the books over. The trap is a parallel run with no end date, where everyone keeps noting things down "their own way, just in case".
List the Excel files still opened every day and ask, for each one, why. The answer is almost always one of these three:
- the person doesn't yet know how to do it in Odoo: that is training, and a quarter of an hour sitting next to them often settles it;
- Odoo can do it, but a setting is missing: that is a small fix to schedule;
- it is habit: the file is faster because they have known it for ten years.
Set an end date for the parallel run, for example the end of the first month, and announce it. From then on, a piece of information only exists if it is in Odoo. The manager sets the example: they ask Odoo for their figures, not a spreadsheet.
Weeks 1 and 2: one owner for each type of record
In Excel, anyone could fix a row. In Odoo, if everyone creates their own customers and products, the duplicates are back within weeks. Name one person for contacts, one for products, one for prices, each with a back-up. Everyone else checks that the record doesn't already exist, then asks.
This is not only about tidiness. Odoo's documentation warns that contacts sharing the same VAT number can distort the VAT report, and recommends parent and child contacts for related companies.
Week 2: bank reconciliation, little and often
Until a bank transaction is reconciled, Odoo keeps it on a suspense account. Waiting for month-end means finding dozens of lines to deal with at once. Ten minutes every two or three days is enough.
For automatic matching, Odoo compares the transaction label with the number, reference or payment communication of invoices when no partner is set. When the partner is known, it looks for an invoice from that partner with the same amount. Two practical consequences: set the partner on transactions that keep coming back, and find out why an invoice wasn't recognised (different amount, free-text communication, grouped payment).
Recurring transactions with no invoice, such as bank fees, are handled with a reconciliation model. And if you have connected CodaBox, Odoo fetches the CODA files every 12 hours: no more importing them by hand.
Weeks 3 and 4: the first VAT return
First check that the periodicity (monthly or quarterly) and the reminder date are set in the accounting settings: Odoo then sends reminders ahead of the deadline.
Before validating, go through the return review. Odoo checks, among other things, for entries still in draft within the period, missing company data, and vendor bills with no attachment, which would be your evidence in an audit.
The first time, go through the result with your accountant. Once the return is validated, the period is locked: a correction to an invoice from that period is recorded in the next period. Better to find the mistake before. While you are at it, check that the aged receivables report lands on the customer account balance, and the same on the vendor side.
All month long: a friction list, reviewed every week
What sends people back to Excel is the small annoyances: a field they can't find, a document printed with the wrong title, a customer they can't locate. Open one place where everyone notes them. Every week, spend fifteen minutes sorting: what takes a minute gets fixed straight away, the rest is scheduled. A friction left unanswered for two weeks is an Excel file coming back into service.
What not to customise in the first month
For a month you are learning how you really work with Odoo, and it is never quite what the original plan said. Customising straight away freezes habits that are still going to change. Leave alone:
- custom fields and screens, until the same request has come from several people;
- custom reports: the standard ones (aged balance, VAT report, sales) cover most of what the first month needs;
- complicated automations: automate what you have already done by hand several times, not what you imagine you will have to do;
- the chart of accounts and default taxes: you can rename an account, but don't delete the ones the standard setup uses.
Do it yourself or buy an hour
Keep in-house whatever concerns how you work: who approves what, how products are named, which customer categories exist.
An outside hour is worth it for a one-off technical problem: a reconciliation model that matches nothing, an import to redo, a first VAT return to read through with the accountant, an error whose cause you can't find. A simple rule of thumb: if a question has already cost you an hour with no answer, the next hour is better handed to someone who knows Odoo. The buying logic is covered in the article on IT hour packs.
If you'd like an outside view on your first thirty days, it is the kind of work we do through hour packs: info@z80.be or +32 494 111 041.