Software maintenance
Enterprise software maintenance: what to include, how much it costs, and how to avoid obsolescence
Published: February 19, 2026
Software maintenance isn't the cost that comes after the project: it's the investment that determines whether that project keeps generating value in 3 years or becomes a legacy system nobody wants to touch. Understanding what to include, how much to budget, and when to evolve is as important as the initial development.
This guide targets CTOs, systems managers, and operations directors at Spanish companies managing custom software or proprietary business applications. If your company has software in production for over 2 years and lacks a clear maintenance plan, now is the time to define one.
Maintenance types and what each covers
- Corrective: bug fixes in production. Must be included in warranty for the first 3-6 months post-delivery.
- Preventive: dependency updates, security patches, and compatibility with new OS and browser versions.
- Adaptive: changes required by regulation, changes in third-party APIs, or cloud infrastructure changes.
- Evolutionary: new features and improvements. This has the highest business impact and requires clear prioritization.
How much to budget: the market standard
- Market standard: 15-20% of initial development cost per year. For a €100k project, budget €15-20k/year.
- Below 10%: you only cover basic corrective. Technical debt accumulates and the system ages faster.
- Above 25%: signal the system has structural issues or the vendor is overbilling hours.
- Always include in budget: third-party dependencies with growing costs (APIs, licenses, cloud compute).
Obsolescence signals every executive must recognize
- The team starts requesting workarounds for tasks 'the system should do': functionality isn't keeping pace with the business.
- Security updates are delayed more than 90 days: exposure risk escalates exponentially.
- New developer onboarding time exceeds 2 weeks: the code is no longer maintainable by anyone new.
- More than 30% of the technical team is afraid to touch certain parts of the system: critical technical debt.
How to evolve software without traumatic migrations
- Semi-annual roadmap review: prioritize evolutionary work in blocks, not feature by feature. More efficient and less disruptive.
- Feature flags for gradual deployments: reduces the risk of each change and allows rollback without downtime.
- Incremental refactor, not total rewrite: replace specific modules while keeping the system in production.
- Updated documentation as a delivery condition: without documentation, future maintenance is more expensive and slower.
Need a maintenance and evolution plan for your enterprise software?