The verdict in three sentences
A maintenance retainer turns an unpredictable expense (the outage that always hits on the worst day) into a fixed monthly cost of 150 to 800 EUR depending on the service level. It covers five pillars: corrective, enhancement, security, hosting/backups and monitoring, with an SLA that commits the provider to response times. Skipping maintenance means betting nothing will ever break: the day a vulnerability is exploited or an update takes the site down, the bill dwarfs a full year of retainer.
What a retainer actually covers in 2026
A serious contract is more than "we check if it works". Here is the typical breakdown of services and their weight in the monthly fee.
| Pillar | What it includes | Frequency | Weight in fee |
|---|---|---|---|
| Corrective | Bug fixes, broken links, 500 errors | On demand, under SLA | 20-30 % |
| Enhancement | Small changes, new pages, tweaks | Monthly hour quota | 25-35 % |
| Security | CMS/plugin updates, patches, WAF | Monthly + emergencies | 20-25 % |
| Hosting | Server, CDN, SSL certificate, domain | Continuous | 10-15 % |
| Backups | Daily backups, tested restore | Daily | 5-10 % |
| Monitoring | Uptime monitoring, alerts, monthly report | 24/7 | 5-10 % |
SLA tiers and their prices
Price depends mostly on the guaranteed time to restore (GTR) and the support channel. Here are the 2026 tiers seen for a brochure site or a high-traffic B2B site.
| Tier | Critical incident GTR | Enhancement hours included | Support | Monthly price |
|---|---|---|---|---|
| Essential | 72 business hours | 1 h | 150-250 EUR | |
| Standard | 24 business hours | 2-3 h | Email + phone | 300-450 EUR |
| Business | 8 business hours | 4-6 h | Priority + on-call | 500-650 EUR |
| Critical | 4 h, 24/7 | 8 h | Dedicated + 24/7 on-call | 700-800 EUR |
Budget tip: an SME brochure site is usually fine on the Standard tier, while a site with forms, payment or a client area justifies the Business tier.
Fixed retainer vs pay-as-you-go hourly work
The question always returns: why pay every month if the site "just runs"? Let us compare over twelve months with a developer day rate of 500-700 EUR.
| Scenario | Detail | Estimated annual cost |
|---|---|---|
| Standard retainer | 350 EUR/month, all included | 4,200 EUR |
| Controlled ad-hoc | 2 interventions/year of 4 h | 4,000-5,600 EUR |
| Ad-hoc + incident | 2 interventions + 1 major outage (2 days) | 12,000-16,000 EUR |
| No maintenance | Vulnerability exploited, partial rebuild | 8,000-25,000 EUR |
The retainer wins as soon as a single serious incident occurs in the year, which is statistically the norm for an unmaintained site (outdated extensions, un-patched PHP). Rough 2026 order of magnitude, excluding brand damage and lost revenue during downtime.
Mini case study
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
Claire, CFO of an industrial SME in Lyon, hesitates to sign a 350 EUR/month retainer for the corporate site that generates 30 % of sales leads. Without a contract, an outdated form plugin gets exploited: the site is defaced for 3 days and forms stop coming through. Emergency recovery cost: 4,800 EUR, plus an estimated 12 lost leads at 1,500 EUR of margin each, i.e. 18,000 EUR. The total, 22,800 EUR, represents more than five years of the Standard retainer. Claire signs and budgets a predictable, deductible 4,200 EUR/year.
FAQ
Is a retainer mandatory after a website rebuild?
No, but strongly advised: 60 to 70 % of CMS site hacks target un-updated extensions. Without a retainer, responsibility for those updates, including urgent security patches, falls entirely on you.
What is the difference between corrective and enhancement?
Corrective returns the site to normal operation (a bug, an error). Enhancement adds value (new page, new field, integration). A good contract includes an enhancement hour quota, typically 2 to 6 h/month rollable over a quarter.
Can I host elsewhere and only take the maintenance?
Yes. Many contracts separate hosting (25-75 EUR/month) from application maintenance. Beware though: if the provider does not control hosting, restore times after an incident get longer.
What happens if I exceed my enhancement hour quota?
Extra hours are billed at the contractual day rate, often with a 10 to 20 % discount versus off-contract ad-hoc work. That is one of the hidden benefits of a retainer.
How long is the commitment?
Most retainers are a 12-month commitment then rolling, cancellable with 1 to 3 months notice. Avoid contracts with no reversibility clause (recovery of code, credentials and backups).
Let's scope your project. Tell us about your site (CMS, traffic, forms, payment) and the uptime you expect, and we will size the right SLA tier. 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.
