The verdict in three sentences
Application maintenance (TMA) of a B2B site in 2026 represents 12 to 20% of the build cost per year, i.e. 150 to 600 EUR/month depending on complexity. This budget covers security, updates, backups, fixes and monitoring: neglecting it exposes you to hacking, downtime and technical debt that makes a rebuild inevitable within 3 years. The real choice is between a predictable monthly retainer and on-demand time-and-materials (day rate 400 to 650 EUR).
What a maintenance contract covers in 2026
Maintenance is not mere hosting: it is an active service contract. Here are the typical services and their budget weight.
| Service | Frequency | Indicative monthly budget (EUR) |
|---|---|---|
| Security updates (CMS, plugins) | Continuous | 40 - 150 |
| Automated backups + restore | Daily | 20 - 60 |
| Uptime monitoring + alerts | 24/7 | 30 - 100 |
| Bug fixes | On demand | 30 - 120 |
| Small changes (content, pages) | Monthly | 50 - 200 |
| Monthly report + support | Monthly | 20 - 80 |
For a brochure site, a 150-250 EUR/month contract is enough. An institutional site with integrations (CRM, advanced forms) justifies 350-600 EUR/month.
Retainer vs time-and-materials: which model to choose
Two models compete. The retainer offers predictability; T&M offers flexibility. Here is the 2026 quantified comparison.
| Criterion | Retainer | T&M (day rate) |
|---|---|---|
| Price | 150 - 600 EUR/month | 400 - 650 EUR/day |
| Budget predictability | High | Low |
| Response time (SLA) | Guaranteed (4-24 h) | Variable |
| Backups / monitoring included | Yes | No (billed separately) |
| Best for | Stable site, controlled budget | Evolving project, big work |
| Typical annual cost | 1,800 - 7,200 EUR | 3,000 - 12,000+ EUR |
The retainer suits 80% of B2B sites. T&M becomes necessary when frequent, unpredictable changes exceed the scope of a retainer.
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Mini case study
Julien, head of a 60-employee industrial SME in Toronto, had his institutional site built for 22,000 EUR. He hesitates over a maintenance contract. One year with no maintenance: his outdated CMS is hacked, the site stays offline for 5 days, and cleanup + restoration costs 4,800 EUR, on top of lost credibility with two prospects. A 280 EUR/month contract (3,360 EUR/year, i.e. 15% of the build) would have prevented the incident. The math is clear: maintenance costs less than repair.
FAQ
What maintenance budget should I plan? Allow 12 to 20% of the development cost per year. A 15,000 EUR site justifies 1,800 to 3,000 EUR/year of maintenance, i.e. 150 to 250 EUR/month.
What happens if I don't maintain my site? Security flaws accumulate, the CMS and plugins become vulnerable, and hacking risk climbs. Add to that technical debt that makes any future change increasingly costly.
Retainer or T&M, which is cheaper? For a stable site, the retainer is cheaper and more predictable. T&M becomes worthwhile if you have frequent, significant changes that would exceed a retainer's volume.
What is a maintenance SLA? It is the contractual commitment on response time: for example, fixing a blocking bug within 4 business hours. The shorter the SLA, the higher the retainer.
Does maintenance include hosting? Not always: some contracts include it, others bill it separately (25 to 75 EUR/month). Always check the exact scope before signing.
Let's scope your project. Tailored maintenance contract for your B2B site, indicative budget 150 to 600 EUR/month depending on complexity and SLA. 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.
