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Technical Debt: How Should You Pay It Back?

Technical debt eventually demands attention, but there is more than one way to settle the bill. Between a major overhaul and gradual improvements, the right choice depends as much on the product’s future as on its technical condition.

The work you postponed has become more expensive

Technical debt begins with work deferred. A platform upgrade, a proper test suite, an architectural improvement or a dependency cleanup can wait because something else matters more today. The immediate benefit is real: a customer receives a new feature, the product ships, or a deadline is met.

The debt appears when that work remains necessary and becomes more expensive with time. Dependencies move on, interfaces change, vulnerabilities are discovered, knowledge disappears and new developments build on assumptions that should have been revisited. The additional effort is the interest on the debt.

Postponing work can be a reasonable decision. The difficulty is that the original saving is visible, while the accumulating cost is spread across maintenance tasks, investigations and increasingly fragile changes. Eventually, a new requirement, a regulatory change, or an operational failure makes the balance impossible to ignore.

True Story

An example: an ageing Yocto platform

Consider an embedded product built on an old Yocto release and a vendor BSP. For years, development has concentrated on the business application. Poky, the BSP and most underlying components have received little attention because the product works and customers keep asking for application features.

Preparing for the Cyber Resilience Act brings the neglected platform back into the discussion. Producing a reliable Software Bill of Materials, or SBOM, and tracking known vulnerabilities becomes difficult with the existing infrastructure. The product still performs its original functions, but maintaining it now requires capabilities that were never developed.

Two approaches are possible. The team could migrate to a recent Yocto release and BSP, obtaining newer components and established mechanisms for SBOM generation and vulnerability checking. Alternatively, it could retain the platform and develop tooling to extract a reliable component inventory, generate an SPDX SBOM and feed a vulnerability analysis tool.

Both approaches can address the immediate need. They leave the product in different conditions for whatever comes next.

Two ways to settle the bill

There is one way to avoid further investment: abandon the product and its maintenance. Users may be left with equipment they can no longer rely on, and ending sales does not necessarily end support obligations. We will leave that option outside this discussion.

For a product that must continue, two broad strategies remain: repay a substantial part of the debt through a major intervention, or repay gradually through focused improvements. There are many combinations between them. The distinction is how much of the existing product is reconsidered, and how much deferred work remains afterwards.

Substantial repayment

A major repayment revisits the foundations. Depending on the situation, this could mean replacing an ageing platform, restructuring an architecture or rebuilding the product entirely. The intention is to remove limitations that repeatedly make development and maintenance more difficult.

The effort is substantial, and some of its scope will only become clear during implementation. Existing behaviour must be understood, adaptations must be made and regressions must be controlled. When the debt includes inadequate testing or lost knowledge, recovering that capability becomes part of the investment.

In the Yocto example above, migrating the BSP changes more than the available tooling. Newer component versions generally incorporate fixes for vulnerabilities present in older releases. One migration can therefore remove part of the security backlog and avoid numerous individual backports, each requiring investigation, adaptation and validation.

The new components will have vulnerabilities of their own. The lasting benefit is returning to maintained versions for which future fixes are more accessible. More generally, substantial repayment should improve the team’s ability to handle the next requirement, rather than merely satisfy the current one.

A major overhaul does not erase every debt. It can also introduce new ones through rushed decisions or insufficient validation. Its value depends on the foundations it restores and the maintenance capacity it creates.

Gradual repayment

Gradual repayment preserves most of the existing product and addresses selected limitations. The team improves what causes the most immediate difficulty, with changes small enough to investigate, validate and deliver separately.

This can produce useful results sooner and reduce the disruption associated with a broad overhaul. It also allows investment to follow actual needs, which can be valuable when the product’s future is limited or uncertain.

In the Yocto example above, dedicated inventory and vulnerability tooling could restore visibility without requiring a platform migration. That visibility would support targeted corrections. It would not, by itself, remove the vulnerabilities or simplify the work of adapting fixes to old components.

The distinction matters beyond this example. An incremental improvement can remove a portion of the debt, reduce its interest or simply make it easier to live with. Those are different outcomes, and the decision should recognise which one is being purchased.

Gradual repayment is sustainable when the remaining limitations are understood and their cost is acceptable. It becomes an endless sequence of workarounds when each intervention is treated as the last temporary fix, while the underlying difficulty remains untouched.

The smaller effort is not always smaller

A major overhaul looks expensive because much of its cost appears in one project. Incremental work distributes that cost across successive tasks, making the initial decision easier to accept. Comparing only the first task gives an incomplete picture.

Dependencies are often more complex than expected. A local modification can affect another subsystem, a supposedly isolated component can depend on an obsolete interface, and an impact analysis can miss behaviour discovered only during validation. Small scope does not guarantee small effort.

The additions made to preserve the existing product also need maintenance. An adapter, a custom tool or a compatibility layer may be justified individually, while their combined cost gradually approaches or exceeds that of a broader intervention.

The comparison must therefore cover the remaining life of the product. Initial effort, recurring maintenance, validation and delivery risk all belong in the calculation. The debt’s interest continues to accrue between interventions.

How much future does the product have?

A product expected to support new features, new customers and several more years of development has a strong case for substantial repayment. The investment has time to produce value through easier maintenance and fewer recurring obstacles.

A mature product approaching replacement may justify a narrower approach. A major overhaul could consume its remaining development capacity and introduce regressions without delivering enough benefit before retirement. Focused improvements may provide a better use of that capacity.

The relevant horizon includes the installed base. A product scheduled to leave the catalogue next year may still require support for many years afterwards. Its commercial lifetime and its maintenance lifetime can be very different.

The decision also depends on what those remaining years will contain. Keeping a stable product operational is a different ambition from extending it into new markets or making it the foundation of the next product generation. The same technical condition can lead to different repayment strategies.

Choose the investment your product needs

Settling technical debt requires a clear view of what the product must still deliver. A major overhaul can restore the foundations for years of development. Gradual improvements can keep a mature product going without committing to a reconstruction whose benefits may arrive too late. Either choice becomes expensive when it rests on an incomplete assessment of dependencies, validation effort or remaining support needs.

The first investment should therefore be in understanding the options. What debt is actually being removed? What will remain? How much will the next change cost? Answering those questions makes it possible to choose a repayment strategy that the business can fund and the engineering team can sustain.

Embedded Expertise brings together technical investigation, architecture assessment and hands-on experience to make that decision concrete. We assess the existing product, expose the constraints and compare credible paths forward, then help implement the chosen approach.

If technical debt is beginning to dictate your roadmap, let’s discuss your product’s next stage.

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