The verdict in three sentences
A 1-to-4 gap between quotes does not mean dishonest vendors: it reveals a poorly described need that everyone interprets differently. A user-story requirements spec with priorities and acceptance criteria costs 3,000 to 8,000 EUR excl. VAT if outsourced, or 5 to 10 days of internal work. With it, quotes converge within plus or minus 20 to 25%, and negotiation finally focuses on scope rather than price.
Why your quotes range from 25,000 to 110,000 EUR
Take a Dublin wine and spirits distributor that wants to centralise orders from restaurants and off-licences, allocations of rare wines, warehouse stock and en primeur tracking. Sent as a two-page email, this need produces incomparable answers: one vendor prices a simple back office, another a platform with a customer portal, ERP connector and mobile app.
| Source of the gap | Vendor's low assumption | Vendor's high assumption | Impact on quote (2026 estimate) |
|---|---|---|---|
| Number of user profiles | 2 roles (admin, sales) | 6 roles with fine-grained rights | +8,000 to 15,000 EUR |
| ERP / accounting integration | Manual CSV export | Real-time two-way API | +10,000 to 25,000 EUR |
| Trade customer portal | None | Online orders, invoices, history | +12,000 to 30,000 EUR |
| Allocation management | Simple table | Automatic allocation rules | +5,000 to 12,000 EUR |
| Legacy data migration | None | 10 years of cleaned Excel history | +3,000 to 8,000 EUR |
| Testing and documentation | Client tests alone | Test plan, training, documentation | +4,000 to 10,000 EUR |
Added together, these six grey areas alone explain 42,000 to 100,000 EUR of gap. Nobody is lying: each developer fills the brief's silences with their own assumptions.
The 5-block requirements spec template
A good document runs 15 to 30 pages. Longer and nobody reads it; shorter and the grey areas come back. Here is the outline we recommend for an SME business app.
| Block | Expected content | Typical length | Internal writing time |
|---|---|---|---|
| 1. Context and goals | Business, current problem, quantified target gains (hours, errors, revenue) | 2-3 pages | 0.5 to 1 day |
| 2. Users and roles | Profiles, number of users, rights per role, mobile or desktop use | 2-4 pages | 1 day |
| 3. Priority features | User stories ranked MoSCoW (Must, Should, Could, Won't) | 6-12 pages | 2 to 4 days |
| 4. Constraints | Hosting, GDPR, existing tools, data volumes, deadline, budget ceiling | 2-4 pages | 1 day |
| 5. Acceptance criteria | For each story: a verifiable acceptance condition | 3-6 pages | 1 to 2 days |
A user story is simple: 'As a sales rep, I want to reserve a wine allocation for a restaurant so that I never exceed the estate's quota.' Each story gets a priority and an acceptance criterion: 'the reservation is rejected if the allocation balance is zero.' This format lets the vendor estimate story by story, usually in days or points, and lets you compare quotes line by line.
Two practical tips: state a budget ceiling (serious vendors then adapt the scope instead of inflating the price) and clearly mark what is out of scope for version 1.
In-house or outsourced: what the document itself costs
| Option | 2026 cost (order of magnitude) | Lead time | Main risk |
|---|---|---|---|
| Written by the managing director | 5 to 10 days of executive time | 3 to 6 weeks | Too solution-oriented, hard to test |
| Written in-house with a structured template | 4 to 7 days | 2 to 4 weeks | Technical constraints forgotten |
| Independent business analyst | 3,000 to 6,000 EUR | 2 to 3 weeks | Quality varies by profile |
| Scoping workshop with an agency | 4,000 to 8,000 EUR | 2 to 4 weeks | Lock-in if the output is not transferable |
| No spec at all | 0 EUR upfront | Immediate | Change requests of 20 to 40% mid-project |
Require that the deliverable belongs to you and can be used by any vendor. A scoping workshop that only produces a sales proposal is not a requirements spec.
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Mini case study
Aoife, managing director of a 30-person wine distributor in Dublin, received three quotes: 25,000, 64,000 and 110,000 EUR. She invests 6 internal days with a structured template, producing 38 user stories, 21 of them 'Must'. Re-tendered on that basis, four vendors answer between 52,000 and 68,000 EUR, shrinking the gap from 85,000 to 16,000 EUR. By moving the trade portal to version 2, she sets version 1 at 48,000 EUR. If avoided change requests on a poorly scoped project are estimated at 25%, about 12,000 EUR, her 6 days of writing pay for themselves many times over.
FAQ
How long should a business app requirements spec be?
For an SME, 15 to 30 pages are enough. What matters is that 100% of 'Must' features have a verifiable acceptance criterion.
Should I share my budget with vendors?
Yes, a budget ceiling such as 60,000 EUR lets vendors propose a realistic scope. Without it, quotes often vary by a factor of four.
What is the MoSCoW method?
It ranks features as Must, Should, Could and Won't. A healthy version 1 usually contains 50 to 60% 'Must' items and defers the rest.
Can the spec change during the project?
Yes, through formal change management: every new story is estimated before it is accepted. Agile projects often keep a 10 to 15% budget reserve for these adjustments.
How long does development take after the spec?
For 30 to 40 user stories, expect roughly 3 to 5 months including testing and go-live. Scoping itself takes 2 to 6 weeks.
Let's scope your project. Send us your need, even as rough notes: we help you structure it into user stories and estimate version 1 with scope, indicative budget and timeline through our quote form. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
