Choose a packaged ERP when your processes match its standard flow. Choose a custom ERP when the way you work is part of how you compete, or when per-user licences keep growing with headcount. The deciding variable is how far your processes differ from the product's model, so measure that before you compare quotes.
The spreadsheet next to the ERP
Walk through any plant or back office that runs packaged software and you will find a spreadsheet beside it. Staff keep it because the official system cannot hold a step they perform every day. It is a signal that the product stopped describing the business at some point.
The cost of that gap rarely appears in the ERP business case. It shows up in four places.
Re-keying
Wherever the product cannot hold a step, someone retypes data from one system into another. A despatch clerk copies a vehicle plan into the transport desk's sheet. A finance executive keys one invoice a second time into a matching sheet. Nobody's job title says data entry, so the hours go uncounted.
Month-end close
The length of the close tells you whether the ERP is the system of record. When closing drags on far longer than the accounting itself needs, the extra days usually go to matching the ERP against the side sheets and deciding which one is right.
Stale figures
If the true figures sit in a workbook, every report starts as an export. A purchase decision then uses stock levels from two days ago.
Single-owner workbooks
The formulas in a workbook often carry pricing rules, credit limits and special cases that are written down nowhere else. When the author leaves, that knowledge goes too.
Measure it in a week
You need four counts and no consultant.
- Spreadsheets that drive a decision or a payment. Skip sheets that are only printouts of system reports. Each maintained sheet marks a place the product did not fit.
- Re-keying points. List each place a person retypes data that already sits in a system, and note how often.
- Close length. Record the working days, then find out how the last three were spent.
- Workbooks with one owner. Name the person for each critical one.
These counts describe your organisation, which a vendor's feature list cannot do.
What drives five-year cost
Comparing a licence price with a build quote leaves out most of the answer. Use this formula instead, and fill every term for both options.
Five-year cost = licences or build + integrations + data migration + upgrades or changes + support + the workaround cost you measured above.
| Term | Packaged product | Custom build |
|---|---|---|
| Users | Licence fees usually rise with each added user | Cost depends on the build and hosting plan, not on user count in the same way |
| Fit | Configuration is cheap; customisation costs money now and again later | Built around your process, so fit work happens once, in the design |
| Integrations | Each connected system is a contract to maintain | Same, but you choose the interfaces |
| Data | Cleaning work follows how clean the data is, whatever the volume | Same |
| Control | The vendor's release calendar sets when you can change | Your repository and your release calendar |
Process variance moves the result more than any other term. A business that already works the way the product assumes gains little from a build. A business with an unusual production, pricing or credit process may find that the product needs heavy customisation from day one.
Why customisation costs more later
A configured setting normally carries through a vendor upgrade. A customised one often breaks. Each major release forces you to re-test your changes, rework them or drop them. Teams commonly meet this when an upgrade they need for a tax or compliance change collides with the changes that made the product usable. Ask any vendor how customisations are handled in an upgrade, in writing, before you sign. For who controls the code afterwards, see who owns the ERP after go-live.
When the product is the right choice
Apply these to your own case.
- A mature product covers most of your requirement through configuration alone.
- The process is not what sets you apart from competitors. General ledger and payroll rarely do.
- The company is still changing shape, so any system built now will describe last year's business.
- Nobody on your side can look after a platform once it is live, and you do not plan to buy that service.
One of these points toward buying. Two make the case clear. For the open-source middle route, see ERPNext, Odoo or custom ERP.
A sequence that makes the decision on paper
- Map the process as performed. Watch the work and record the exceptions. The normal path is the easy part.
- Split legal requirements from habits. Several supposed product gaps turn out to be habits.
- Price the workaround cost with the four counts above.
- Run a fit-gap against the product, listing what needs customising, as opposed to configuring.
- Decide. A short gap list points to the product.
Even when you buy, the fit-gap document pays for itself, because it becomes the requirements list for the implementation. The cost side is covered in custom ERP cost drivers, and the delivery side in the custom ERP implementation guide.
Questions buyers ask
At what point does custom ERP cost less than a packaged one?
When user counts are large enough that licences keep rising, when staff already run parallel spreadsheets, or when your key process does not fit the product. Run the five-year formula with real quotes to see where yours lands.
How do I know what template software costs us?
Take the four counts: maintained spreadsheets, re-keying points, close length and single-owner workbooks.
Should we keep our current packaged ERP?
Keep it if configuration covers nearly everything and the process is not one that sets you apart. If you are unsure, start with the fit-gap list.
Where Brihat Infotech fits
Brihat Infotech builds custom ERP systems around the way a plant or office actually runs, with the code in your own repository and no per-user licence. Start a conversation.