The verdict in three sentences
A credible maintenance retainer clearly separates corrective work (bugs, security, uptime) from enhancement work (new features, pages, integrations). The classic trap: paying EUR 1,800/year for a retainer that only covers corrective work, then being billed for every small change at EUR 90/hour. Demand a quantified SLA (guaranteed response time), a block of enhancement hours included, and a tested backup/restore clause.
Corrective vs enhancement: the distinction that costs money
| Element | Corrective maintenance | Enhancement (retainer) |
|---|---|---|
| Purpose | Fix what exists | Add / evolve |
| Examples | Display bug, security flaw, downtime | New page, form, module |
| Typical billing | Annual flat fee | Included hours + T&M beyond |
| Expected timeframe | Per SLA (urgent) | Planned (sprints) |
| Risk if absent | Vulnerable site | Every change billed individually |
| Ballpark | EUR 600-1,500/year | EUR 1,200-3,600/year |
SLA tiers and 2026 pricing
Estimates for an SMB brochure site on the European market (London and region).
| Tier | Response time | Guaranteed uptime | Included | Indicative price |
|---|---|---|---|---|
| Essential | 48 business hours | Best effort | Security updates, weekly backup | EUR 900/year |
| Standard | 24 business hours | 99.5% | + monitoring, 6h enhancement/year | EUR 1,800/year |
| Business | 8 business hours | 99.9% | + daily backup, 12h enhancement | EUR 2,800/year |
| Critical | 4h (7 days) | 99.9% | + on-call, 20h enhancement, reporting | EUR 3,600/year |
Included vs excluded
| Included in a good retainer | Often excluded (check) |
|---|---|
| CMS and plugin updates | Full redesign |
| Security patches | Major new modules |
| Backups + tested restore | Content writing |
| Uptime monitoring + alerts | SEO/Ads campaigns |
| Ticket support | In-depth training |
Mini case study
Sophie, procurement lead at a consulting firm in London (30 staff), compares two offers. Offer A: EUR 1,200/year, corrective only. Offer B: EUR 1,800/year with 6h enhancement included and a 24h SLA. In year one she expects 5h of small changes. With offer A those 5h are billed at EUR 90 = EUR 450 extra, total EUR 1,650, with no SLA. Offer B costs EUR 1,800 but covers everything with a response guarantee. She picks B: +EUR 150 for a guaranteed timeframe and zero billing surprises.
FAQ
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
What budget should I plan for brochure-site maintenance?
Count on 12-18% of the build cost per year. For a EUR 10,000 site that is EUR 1,200-1,800/year, excluding major enhancements.
Is an SLA really useful for an SMB?
Yes as soon as the site generates leads. A 24h outage on a site with 30 leads/month can cost one lead at EUR 400 margin. An 8h SLA pays off fast.
What happens if I take no maintenance at all?
The site stays online but accumulates vulnerabilities: an un-updated CMS is the leading cause of hacks. Post-incident recovery averages EUR 1,500-4,000.
Can I switch vendor for maintenance?
Yes, provided you own the code and hold the accesses. Add a reversibility clause: documentation, exports and access transfer within 15 days.
Are unused enhancement hours carried over?
It depends on the contract. The best retainers roll over up to 50% of unused hours to the next quarter. Negotiate this before signing.
Let's scope your project. Send us your current contract or your needs (SLA tier, enhancement volume) and we'll propose a clear, priced, trap-free retainer. 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.
