The Cost of Waiting Belongs Beside the Fear of Replacing. Four Ways Forward, Weighed.
Retailers weigh the cost of replacing an old system and leave the cost of keeping it blank. Here is what waiting costs, one fixed date that does not wait, the four ways forward weighed, and the benchmark for the decision.
The finance head is writing the paper for the board’s annual look at the old order and stock system.
One column is easy to fill. A supplier has quoted for a full replacement, with a single figure and a single date. The other column, the cost of keeping the old system another year, has one line: the support fee.
It does not show the one developer who understands the returns rules, the trade portal that reaches the accounts only through a monthly export, or the delivery option dropped because the old system could not carry it. The board will compare one large number with one small one, and choose the small one again.
The paradox: The cost of replacing is counted to the last line, and the cost of waiting is counted as if it were nothing.
What We Found
We looked at what the public record says about the cost of replacing retail systems, about why firms wait, and at one fixed date that applies to some sellers.
The figures that frighten boards come from one kind of project. A large UK grocer moved off systems it had shared with a former owner, onto a packaged ERP product. By the end of 2025 the work had cost it more than £1 billion, and its leadership said the work delayed its recovery. This was a packaged ERP product at a very large firm, changing a great deal at once.
Firms wait because the system works, and because of money. In one survey of about five hundred IT professionals in the US, half said the biggest reason they had not upgraded was that the current system still works. Budget limits were named by more than two in five. The survey covers many sectors, and was run by a firm that sells software services.
Old technology is said to hold mid-size firms back. In one vendor-sponsored survey of a few hundred leaders at mid-size US and UK manufacturers, retailers and wholesalers, about seven in ten agreed that outdated technology is holding them back.
Some dates do not wait for anyone. Saudi Arabia’s tax authority announced on 24 July 2026 that its e-invoicing Wave 25 covers “taxpayers whose revenues subject to VAT exceeded (SAR 187,500) during 2022, 2023, 2024 or 2025”. The authority will notify those taxpayers to integrate their e-invoicing solutions with its platform “by no later than February 1, 2027”. It is a Saudi rule, and the only one of its kind we use here.
What our review does not show: We do not compare the grocer’s outflow with any earlier figure, and we did not examine why it reached that sum and draw no cause from it; it was a packaged ERP programme at a very large firm, not the kind of work we describe. We found no figure for what keeping an old system costs a mid-size retailer, and no case of a retailer replacing its own application. The Saudi rule is taken from the authority’s announcement; we did not confirm whether shop-till invoices are covered, and no source ties it to any retailer’s old system. The link is our reading.
What Waiting Costs
Beside a large replacement figure, keeping the old system looks cheap. Our reading is that most of what waiting costs is never written down.
The people. An old application is often understood by a few people, sometimes one. When they leave, what the system does leaves with them.
The ideas. A new delivery option or trade channel is built on the old system or not built, and the dropped ones appear in no budget.
The dates set by others. Our reading, and only that: a seller covered by Saudi Arabia’s Wave 25 whose billing system reaches the accounts only by an export may find that the date to connect its invoicing to the authority’s platform arrives before any replacement is ready. Whether the rule applies to your business, and what it requires of it, is for you and your advisers. The date is the point here: it does not move because a board has said “not this year”.
The gap we see: judged against one large figure for replacing everything, waiting always wins. Judged against the full cost of waiting, and a replacement bought one module at a time, it is a different decision. The opportunity is to put both columns before the board with real lines in each, and to make the first commitment small enough to stop after.
This is our reading of the evidence. It is not a measured market figure, and we do not put a rupee value on it here. That figure has to come from your own business.
Four Ways to Replace an Old Retail System, Weighed
| Option | When it fits | What it risks |
|---|---|---|
| Put in a packaged system all at once | The business runs close to the way the product expects, and can carry one large commitment | The whole sum is committed before the old system has been read. What nobody listed arrives as change requests |
| Keep the old system and patch around it | The system is stable, its experts are still there, and no fixed date is near | The cost of waiting stays unwritten. A date set by someone else can arrive first |
| Replace in phases without first writing down what the old system does | Parts of the system are well understood and well separated | Each phase is priced on memory. Unknowns surface one phase at a time, as revised forecasts |
| Write the specification first, then replace module by module, billed by milestone, with a pause after any accepted module | The application is the firm’s own, much changed, and the business cannot stop trading | It costs money before anything new is built. The specification may show more work than the first quote assumed, and old and new run side by side for a time |
Our recommendation: write the specification first, so the price is set after the old system has been read. Then replace the application module by module, billed by milestone, each milestone tied to a module you accept, with the freedom to pause after any accepted module. This is for applications a retailer built or had built; we do not implement packaged ERP or shop platforms, which is what every public case here involved.
Where You Are Now, and Where You Should Be
Before the next year on the old system is agreed, we would set a benchmark for the decision itself.
| Measure | Typical starting point | Where it should be | How it is checked |
|---|---|---|---|
| The cost of waiting | The support fee alone | The fee, workarounds, ideas dropped and the people the system depends on, in one place | The cost comparison |
| The cost of replacing | One figure for everything, set before anyone read the system | A price for each stage, set after the system has been read | The staged plan and quote |
| Unknowns | Found after the contract, as change requests | Listed before the price, with what each could change | The risk register |
| The size of one commitment | The whole replacement at once, or nothing | One module, with the freedom to pause after any accepted module | The staged plan |
| Dates set by others | Not linked to any part of the system | Each listed against the part of the system it reaches | The risk register beside the staged plan |
The starting points above are what we expect to find. In an engagement they are replaced by your own position, taken in the first review. The targets are what we would work towards with you. They are not results we have already achieved for a retailer.
How We Work With You
- We listen: a free Reliability Review. A first conversation about the system and the two columns on the board’s paper. You leave with a short written note of what we found. You can start with a conversation about the system; we ask for read-only code access only when the assessment begins.
- We research. We research your sector, the regulator’s position and what the public record says about firms in your situation. This article is an example of that work.
- We read the system and propose: the Legacy System Specification Assessment. Here the system is the order, stock or trade application you built or had built. It produces a written specification of what it does, a risk register, a cost comparison between keeping and replacing the system, and a staged plan with a fixed quote. AI does a first pass, our senior engineers review it and trace it to the code, and your own experts confirm it. Code access is read-only and logged, never used for training, and deleted within 30 days of the evaluation ending unless we engage. You get the options and our recommendation.
- If you approve, we build. We replace a system one module at a time while the old one keeps running. Here that means your own application, rebuilt beside the old one on technology that is still supported. We never do a single cutover. The work is billed by milestone, each milestone tied to a module you accept, and you can pause after any accepted module.
- We review against the benchmark. Before work starts we set the benchmark. After each module we show you where each measure stands, and the filled-in benchmark is yours at the end.
The Review is free. Every paid step is fixed price, agreed at scoping. Stop after any step. The findings are yours. The assessment fee is credited in full against the first build stage if it starts within 90 days of the report.
What you need to bring: a budget for the assessment, approved separately from any replacement; read-only access to the code once the assessment begins; time from the people who know the system; and your own team or supplier to keep the old system running until each module is accepted, at your cost.
What we do not do: we do not implement packaged ERP products or shop platforms, and every case in this article was one. We do not keep the old system running or secure while the work goes on. We do not train store or warehouse staff or manage the change in how people work. The assessment will not remove every unknown; it tells you which ones remain. Meeting Saudi Arabia’s e-invoicing rules, or any other rule, is your own work: we do not offer a compliance service, and we do not say what any rule requires of a particular firm. We have no published case of this work for a retailer.
What changes for the business:
| Role | What they gain |
|---|---|
| CEO | A figure that can be put to the board and the investors, approved one stage at a time. |
| CTO or CIO | An estimate built from what is in the system. Nobody has to own a guess. |
| CFO | A price for each stage, decided one stage at a time, in place of one figure revised halfway through. |
| COO | Running old and new side by side is priced into each stage from the start, so it is not the first thing cut. |
| Head of marketing | Marketing’s plans for the year do not hang on a project budget that may be reopened. |
The cases in this article, and what IOanyT does about that kind of problem:
| The case | What IOanyT does |
|---|---|
| At a large UK grocer, moving off systems it had shared with a former owner, onto a packaged ERP product, cost more than £1 billion by the end of 2025. | Our part is far narrower than this case: we do not implement packaged ERP products, and we do not say why that project cost what it did. For applications a retailer built or had built, we read the system before we price, list the unknowns in a risk register and price each stage. |
| Saudi Arabia’s tax authority announced on 24 July 2026 that it will notify the taxpayers in its e-invoicing Wave 25 to integrate with its platform “by no later than February 1, 2027”. | Our assessment shows where a business’s invoicing sits in its own application and what replacing that part would take. Meeting the rule is the seller’s own work. |
IOanyT is a consultancy with its own engineering team: we study the problem, recommend, and prove it by building only what you approve. We put both columns in front of your board.
Sources
- Trade press, 2026
- A vendor's survey, 2025
- News report of a vendor-sponsored survey, March 2025
- ZATCA, 24 July 2026
In this issue
Replacement is costly and disruptive
Research note 1
Every Retail Replacement Story You Have Heard Is One Kind of Project. Yours Probably Is Not.
Every named retail replacement failure is a packaged ERP at a very large firm. What we found, why retailers wait, the options, and the benchmark we would set.
Research note 3
A Replacement You Can Pause Is One You Can Start. The Measures to Hold It To.
Percentage complete tells a board little. The benchmark we would set for a retail replacement: accepted modules, a price per stage, and a point to pause.
Issue study
Replaced All at Once
Retail system replacements that cost heavily and disturbed trading, why firms wait, the one fixed date that does not, the options and our benchmark.
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