The short answer: a packaged ERP such as Odoo or Zoho is usually the right choice for businesses whose operations broadly match standard practice for their industry. A custom ERP makes sense when your sales models, pricing or operations are unusual enough that a packaged implementation would require heavy customization — at which point you're paying for a product and custom development at the same time.
Standard modules for sales, inventory, purchasing and accounting; quicker starts; ongoing vendor updates; established implementation partners. For many businesses, that's the sensible route.
The warning sign is an implementation plan full of customization. Heavily customized packaged ERPs combine the costs of both approaches: licensing, plus custom development, plus the risk that vendor upgrades break your customizations.
| Risk | Mitigation |
|---|---|
| Large, risky switchover | Phased delivery, starting with one module |
| Figures don't match | Parallel running until reconciled |
| Dependence on one developer | Full source code and documentation handed over |
| Scope growth | Fixed scope per phase |