Software maintenance cost and support after launch

The launch is not the finish line. Software needs hosting, security patches, bug fixes, and small changes for as long as you use it - and that ongoing cost surprises owners who only budgeted for the build. Here is what maintenance actually costs, what a monthly plan covers and what is billed by the hour.

Quick answer

• Annual maintenance usually runs 15-25% of the build cost.
• For a system built for €40,000 that is €6,000-€10,000 a year, or about €500-€833 a month.
• Monthly maintenance covers monitoring, security updates, tested backups, bug fixes and agreed hours for changes.
• Response times are written into the contract by urgency; our base level responds within one working day.
• Work outside the agreed plan is billed hourly at €40-60 excluding VAT.

The 15-25% rule

A widely used benchmark: annual software maintenance runs 15-25% of the original development cost. Build something for €40,000 and a realistic support budget is roughly €6,000-€10,000 per year. Over a full lifecycle, maintenance often totals 2-4x the original build - which is why the cost of building is only part of the picture.

That range moves with code quality, age, and how critical the system is to your business. Clean, well-tested code stays near the low end; neglected code drifts upward every year.

Support after launch: the first months

The first months after go-live are the busiest. Real users find bugs testing missed, requests for small changes arrive, and load and data are real for the first time. That is why it helps if the team that built the system stays with it at least until things settle.

After that the work changes: fewer urgent fixes, more routine upkeep and new features. That is the point where moving to a monthly partnership makes sense. How to make the first weeks easier for users is covered in software adoption after a custom build.

What monthly maintenance covers

Good business software maintenance is not just firefighting. In our monthly software maintenance and development partnership it means:

• Monitoring and alerts - we hear about a problem before your customers do.
• Security updates - frameworks, libraries and servers on a schedule.
• Tested backups - kept off the main server, with restores we actually test.
• Bug fixes by priority.
• Monthly hours for changes and new features, planned with you.
• Regular reviews of work done, the roadmap and building risks.

The monthly amount depends on the systems and scope; we agree it in writing up front and it does not change without your consent. On top come the costs of running the system itself (hosting, domains, third-party services), broken down in hosting and running costs after a custom build.

Response times and what an SLA buys

A Service Level Agreement defines response and resolution times - not a vague promise to “fix things”. It sets priority tiers (critical outage vs minor bug), guaranteed response windows, support hours, and who pays for what. Higher guarantees cost more because they reserve people and faster escalation paths.

Our base maintenance level responds within one working day; higher levels get a faster response for urgent failures and priority response. Match the SLA to the real cost of downtime: a booking system losing sales every minute justifies tighter terms than an internal report. What the contract itself must say is covered in software maintenance contract and SLA.

What is billed hourly

Anything outside the agreed plan - a larger new feature, a one-off migration, an urgent intervention outside the agreed terms - is done hourly at €40-60 excluding VAT, depending on the kind of work. We agree an estimate of hours before starting, and every month you get a list of tasks and hours spent.

Worked example: a €6,000-€10,000 annual budget for a €40,000 system means €500-€833 a month. At €40-60 per hour that is roughly 8-21 hours of work a month - enough for monitoring, updates and small changes on a stable system. If the wish list grows faster, plan more hours up front instead of paying for them as urgent work.

What drives the number up

• Technical debt. Rushed or legacy code can demand 30-40% per year - sometimes the signal it is cheaper to rebuild.
• Regulation. Compliance, audits, and security reviews add fixed overhead.
• Uptime expectations. A system needing 24/7 response costs far more than one with business-hours support.

If your current supplier did not build the system, maintenance starts with a review of the code and infrastructure. How that works is on the software takeover page and in taking over software from another agency.

Software maintenance is not IT system maintenance

IT system maintenance usually means computers, the network, printers and Microsoft 365 - that is the job of IT support. Business software maintenance covers the applications, web shops and automations someone built for you. We only do software; keep your IT support, and we coordinate with them where the two meet.

Frequently Asked Questions

Is maintenance really 15-25% every year? For most custom software, yes. Simple, well-built systems sit near 15%; complex, regulated, or aging ones climb to 25% or more.

Can I skip maintenance to save money? Only briefly. Skipped security patches, broken connections to other systems, and accumulating bugs cost more later - often a forced rebuild instead of steady upkeep.

How much does monthly maintenance cost with you? The monthly amount depends on how many systems there are, how critical they are and how much development you want each month, so there is no price list for plans. We agree it in writing before starting, and anything outside the plan is billed at €40-60 per hour excluding VAT.

Do you maintain software someone else built? Yes. We start with a review of the code, infrastructure and access, fix what is urgent, document what is missing and then take over regular maintenance.

What is the difference between support and maintenance? Support answers problems and questions as they arise; maintenance is the proactive work - updates, monitoring, fixes - that prevents them. A good plan covers both.

Related Articles

• How much does custom software cost in Croatia?
• Hosting and running costs after a custom build
• Legacy system migration: rebuild or keep?

Planning support after launch?

We scope maintenance and response times around your real risk - a predictable monthly amount, clear response times, no surprises after go-live. See how monthly software maintenance and development works, or reach out at info@tsunami-digital.com or via the form on our homepage.