The verdict in three sentences
In 2026, maintenance and support for a custom application costs 15 to 22% of the build cost per year, i.e. €12,000 to €26,000 for an app built at €100,000. A maintenance package runs €800 to €3,000/month depending on the SLA, and time-and-materials changes €500 to €750/day. A 24/7 on-call adds 30 to 50%: only pay for it if your app is genuinely critical at night and on weekends.
What maintenance really covers
Many IT directors confuse corrective maintenance (fixing bugs) with evolutionary maintenance (adding features). A clear contract separates three blocks: corrective, evolutionary and user support. Here are the 2026 benchmarks.
| Maintenance item | Scope | 2026 benchmark (€) |
|---|---|---|
| Corrective (bugs, security) | Fixes, patches, dependencies | 5,000 - 12,000 /yr |
| Evolutionary (small features) | Tweaks, new fields, reporting | 6,000 - 14,000 /yr |
| User support (L1/L2) | Hotline, tickets, guidance | 3,000 - 9,000 /yr |
| Hosting + monitoring | Cloud, supervision, backups | 1,800 - 9,000 /yr |
| 24/7 on-call | Night/weekend intervention | +30 to 50% of package |
For a €100,000 app, a corrective + evolutionary + support contract runs around €18,000/year, i.e. 18%. Below 12%, be wary: the vendor usually cuts response times.
Choosing the right SLA tier
The SLA (Service Level Agreement) sets response and resolution times. Paying for a "platinum" SLA on a non-critical tool is waste; the opposite can cost a fortune on an outage day.
| SLA tier | Response | Major incident resolution | Monthly budget |
|---|---|---|---|
| Essential | Next business day | 3 - 5 days | €800 - 1,200 |
| Standard | 4 business hours | 1 - 2 days | €1,300 - 2,000 |
| Premium | 2 business hours | 4 - 8 h | €2,100 - 3,000 |
| Critical 24/7 | 1 h, 24/7 | 4 h, 24/7 | €3,000 + on-call |
Simple rule: if a one-day outage costs less than €2,000, stay on Standard. If it blocks billing or production, move to Premium.
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Mini case study
Sophie, IT director of a services SME in Paris, had a client portal built for €110,000. She's torn between a Standard package at €1,700/month (€20,400/year) and ad-hoc time-and-materials. Last year the app needed 14 fixes and 9 small evolutions; on pure T&M, at €650/day and about 32 cumulative days, the bill would have hit €20,800 with no response-time commitment. The Standard package, at near-identical budget, guarantees a 4-hour response and smooths cash flow: she signs it.
FAQ
Is maintenance mandatory? No, but without it an app degrades: unpatched security holes, obsolete dependencies, technical debt. Budget at minimum corrective maintenance at €5,000-12,000/year.
Package or time-and-materials? A package secures response times and smooths budget; T&M (€500-750/day) suits rare, unpredictable needs. Beyond ~25 days/year, a package is usually better value.
Is 24/7 on-call worth it? It adds 30 to 50% to the package. Only take it if a nighttime outage has a real business cost: e-commerce, logistics, healthcare.
Can we switch maintenance providers? Yes, if the code is documented and belongs to you. Plan 5 to 15 days of handover (knowledge transfer) depending on complexity.
How do we budget 3-year TCO? Build cost + (18% × build × 3). For a €100,000 app, count roughly €154,000 over 3 years, hosting included.
Let's scope your project. Tell us your app's build cost, its criticality and usage hours: we'll propose the right SLA tier and a priced maintenance package. 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.
