Where the months go
| Phase | What is happening | Typical span |
|---|---|---|
| Discovery | Process, data, integrations, definition of the first live slice | 2 to 6 weeks |
| First slice | Build, migrate a usable data set, train the people who will actually use it | 8 to 16 weeks |
| Parallel run | Old and new side by side until the numbers match | 2 to 6 weeks |
| Next modules | Accounts, production, branches — one at a time | Ongoing |
The phase that gets skipped is parallel run. Skipping it is how you go live on a Monday and discover on Thursday that stock was never right.
Costs that are not the software
- Cleaning and migrating data. Always larger than the first conversation implied.
- Staff time. Someone from the business has to sit with the build. If they cannot, the system will encode guesses.
- Integrations — Tally, banks, e-commerce, weighing scales, whatever is actually in the room.
- Training and a written operating procedure. Software without that becomes optional in a month.
Licence fees on a package are visible. These items are not, and they appear on custom and package projects alike. See custom versus SAP versus Odoo before you compare two quotes that are not measuring the same thing.
For the broader “what are we even building” question, start at what custom ERP is.