The verdict in three sentences
For a B2B website that produces a meaningful share of your leads, a monthly retainer with an SLA is almost always more cost-effective than pure hourly billing, because it buys availability, not just hours. Time-and-materials work still makes sense for one-off, well-scoped improvement projects. The right setup in 2026 combines a retainer of 250 to 450 EUR per month with a block of day-rate days approved once a year.
What each model actually covers
The confusion usually comes from the word "maintenance". It covers corrective work (fixing), preventive work (updating, backing up, monitoring) and evolutive work (adding features). A retainer mostly covers the first two, plus a small volume of improvements. Hourly billing charges for time spent, with no commitment on outcome or response time.
| Criterion | Essential retainer | Business retainer | Premium retainer | Day rate |
|---|---|---|---|---|
| 2026 price (excl. VAT) | 150 to 250 EUR / month | 300 to 450 EUR / month | 500 to 600 EUR / month | 450 to 650 EUR / day |
| CMS and plugin updates | Monthly | Weekly | Weekly + testing | On request |
| Backups | Daily, 30 days | Daily, 90 days, off-site | Hourly + tested restore | Not included |
| Uptime monitoring | Email alert | 24/7 alert, every 5 min | 24/7 + on-call | Not included |
| Included improvement hours | 2 h | 4 h | 6 h | Billed as used |
| Response time, blocking issue | 2 business days | 8 business hours | 4 business hours | Depends on availability |
| Monthly report | No | Yes | Yes + recommendations | No |
The line that matters most for a mid-sized company is the guaranteed response time. Without it, an hourly contractor can legitimately get back to you next week.
The cost of a 48-hour outage
To decide, you need to price the risk. Take a B2B website that generates 30% of the leads of a distribution company with 40 million EUR in revenue. The figures below are 2026 estimates to adjust to your own conversion rates.
| Item | Assumption | Impact of 48 h downtime |
|---|---|---|
| Lost leads | 60 leads per month, 30% from the site | about 4 leads |
| Win rate | 20% | 0.8 deal |
| Average B2B order | 12,000 EUR | about 9,600 EUR of revenue delayed or lost |
| Gross margin | 25% | about 2,400 EUR of margin |
| SEO | 5xx errors seen by Google | Temporary ranking drop, 1 to 3 weeks |
| Internal crisis time | 2 people x 1 day | about 800 EUR |
| Emergency hourly repair | 1.5 days x 650 EUR | 975 EUR |
A single outage of this kind costs about 4,000 EUR, the equivalent of 10 to 15 months of a Business retainer. Typical causes in 2026: an outdated WordPress plugin exploited by a bot, an expired SSL certificate, an exceeded hosting quota, a form broken by a PHP update.
SLA and exit clauses to demand
A retainer is only as good as its contract. These clauses separate a real commitment from a line on an invoice.
| Clause | Recommended wording | Why |
|---|---|---|
| Response time | 4 business hours for a blocking incident | Limits downtime to half a day |
| Resolution time | 1 business day for blocking, 5 days for minor | Separates pick-up from fix |
| Penalties | 10% of the monthly fee per day late, capped at 50% | Aligns incentives |
| Hour rollover | Unused hours carried over for 3 months | Avoids paying for nothing |
| Reversibility | Handover of access, code and backups within 10 days | You stay the owner |
| Notice | 1 to 3 months, no commitment beyond 12 months | Keeps an exit open |
Also require an operations document: list of access credentials, installed versions, restore procedure. It is what makes switching providers possible without starting from scratch.
Mini case study
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
Emma, marketing manager at a London electrical equipment distributor, used to pay for maintenance by the hour: about 5 days a year at 600 EUR, or 3,000 EUR, with no monitoring. In 2025, two incidents (a contact form broken for 6 days, then a hacked plugin) cost her around twenty leads and 2 days of emergency repairs.
In 2026 she moves to a Business retainer at 390 EUR per month, or 4,680 EUR a year, with 4 hours of improvements per month and an 8-business-hour SLA. She adds 3 day-rate days for a product page redesign, 1,650 EUR at 550 EUR a day. Total budget: 6,330 EUR, versus 3,000 EUR plus incident costs estimated at 7,000 EUR. The 48 hours of yearly improvements also let her launch 2 landing pages per quarter without a new quote.
FAQ
What budget should I plan for B2B website maintenance in 2026?
Plan for 150 to 250 EUR per month for a simple brochure site and 300 to 600 EUR for a lead-generating site with forms, a connected CRM and an SLA. Beyond that, you are looking at application maintenance quoted separately.
Is hourly billing cheaper than a retainer?
On paper yes, if you have no incidents: 2 to 3 days a year at 550 EUR cost less than a retainer. But hourly billing includes neither monitoring nor guaranteed response time, and a single 48-hour outage can cost more than 4,000 EUR.
What does a 4-business-hour response time mean?
The provider commits to start handling a blocking incident within 4 business hours of the report, for example before 1 pm for an alert received at 9 am. It is not a resolution time, which must be set in a separate clause.
What happens if I switch providers?
With a reversibility clause, you recover access, source code, database and backups within 10 days. Without it, a takeover can cost 2 to 5 days of audit, or 1,000 to 3,000 EUR.
Are unused improvement hours lost?
It depends on the contract. Negotiate a 3-month rollover: on a 4-hour monthly retainer, that is up to 12 hours available for a small project.
Let's scope your project. Send us your website URL and lead volume: we will price a maintenance retainer with a matching SLA, from 150 to 600 EUR per month, and a 2-week takeover plan. 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.
