The verdict in three sentences
In 2026, modernizing a legacy application (old PHP, Access, VB) offers two paths: progressive refactoring (40,000 to 90,000 EUR, 6 to 10 months) or a full rewrite (90,000 to 250,000 EUR, 10 to 18 months). The status quo is never free: technical debt inflates maintenance by +25 %/year and exposes you to security flaws. The strangler-fig approach (module-by-module replacement) reduces risk and smooths the budget better than a big-bang.
Strangler-fig vs big-bang: the numbers compared
Two modernization strategies, two risk and cost profiles. Here is the 2026 comparison for a mid-size business application.
| Criterion | Strangler-fig (progressive) | Big-bang (rewrite) |
|---|---|---|
| 2026 budget (EUR) | 40,000 - 90,000 | 90,000 - 250,000 |
| Timeline | 6 - 10 months | 10 - 18 months |
| Service-disruption risk | Low | High |
| Value delivery | Continuous | At project end |
| Old/new coexistence | Yes | No |
| Best when | Critical app in production | Obsolete, disposable app |
For an application used daily in production, strangler-fig avoids the air pocket of a full switchover.
The hidden cost of the status quo
Keeping a legacy app "because it works" has a measurable price. Here are the cost items of inaction over one year, based on an 8-year-old application.
| Debt item | 2026 annual impact |
|---|---|
| Maintenance surcharge | +25 % vs modern stack |
| Cloud migration (if legacy on-prem) | +15,000 - 40,000 EUR |
| Security-breach risk | Potential GDPR fine |
| Hiring difficulty | +20 - 40 % time-to-hire |
| Slow evolution | +30 - 60 % time/feature |
| Blocking outage | 1-5 days downtime possible |
An app whose maintenance costs 20,000 EUR/year on an old stack thus "burns" 5,000 EUR/year in surcharge — not counting the risk of a major incident.
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Mini case study
Karim, IT director of a logistics SME in Dublin, runs a 10-year-old PHP/Access application to manage 15,000 shipments/month. Annual maintenance reaches 22,000 EUR and two security flaws were found. He compares: a big-bang rewrite at 160,000 EUR (14 months) against a strangler-fig at 72,000 EUR (8 months) + 22,000 EUR cloud migration.
He chooses strangler-fig at 94,000 EUR total, replacing the shipping module first, then the back office. By removing 5,000 EUR/year of maintenance surcharge and avoiding an estimated 30,000 EUR outage, the project pays back in around 3 to 4 years, while keeping the application operational throughout the migration.
FAQ
Refactoring or rewrite: how to choose? If the code is structured but ageing, refactoring (40-90k EUR) is enough. If it is unreadable or on a dead technology, a rewrite (90-250k EUR) is unavoidable despite the cost.
How much is cloud migration? Count on 15,000 to 40,000 EUR more depending on complexity. Cloud then cuts infra and security costs by 20 to 35 %/year.
Is strangler-fig always cheaper? Not always in total, but it smooths spending and reduces risk. On a critical app, that smoothing is often worth any slight premium.
What is the real risk of the status quo? Beyond the +25 %/year surcharge, it is the security flaw: a GDPR fine or data breach can cost far more than a modernization.
How long does a modernization take? From 6 to 18 months depending on approach and size. A 3-month promise for a 10-year-old app is almost always underestimated.
Let's scope your project. Tell us about your current application (tech, volume, criticality); we price refactoring (40-90k EUR) or a rewrite (90-250k EUR). 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.
