Technical debt can be diagnosed without being a developer: you only need to watch for business signals — changes that keep getting more expensive, recurring bugs, dependence on a single person, fear of deploying. If you recognise three or more of the eight signs described below, an audit of your IT system is in order: not to rewrite everything, but to make the debt visible, quantified and prioritisable.
What exactly is technical debt?
Every shortcut taken to ship faster — untested code, a postponed upgrade, an architecture patched together as a stopgap — is a loan against the future. Like a financial loan, it carries interest: every future change costs a little more. Debt is not a fault in itself; it becomes a problem when it accumulates without being measured or repaid. Some debt is even taken on deliberately and wisely, to hit a market window; the key is knowing it exists and planning its repayment.
The 8 signs that should alert you
1. Every change costs more than the previous one
A feature comparable to one delivered in a week two years ago now takes three. If the estimates from your team or your vendor keep inflating for a constant scope, the interest on the debt is eating your budget.
2. The same bugs keep coming back in the same place
A module that needs fixing every couple of months is not unlucky: its design no longer withstands real-world cases. Successive fixes pile up like patches on a worn-out inner tube.
3. Everything rests on a single person
If only one developer — in-house or external — knows how the core of the system works, your company has a human single point of failure. Holidays, resignation, a commercial dispute: the risk is permanent and grows over time.
4. Upgrades have been postponed for years
An end-of-life framework, an unmaintained PHP or Node version, frozen dependencies: every month of delay makes the upgrade riskier and more expensive, while exposing you to publicly documented security vulnerabilities. The cost of catching up grows faster than linearly: skipping one major version is manageable, skipping three is a project in itself.
5. The application keeps getting slower
Slowdowns that worsen with data volume or user count usually reveal structural choices — unoptimised queries, no caching, a saturated architecture — that no bigger server will durably compensate for.
6. Deploying is scary
If every release is a dreaded event, scheduled at night, with an uncertain rollback, then neither tests nor automation are playing their safety-net role. Fear of deploying is paid for in features shipped less and less often.
7. A new developer takes months to become productive
An endless onboarding signals unreadable code, missing documentation and development environments that cannot be rebuilt. It is also an excellent predictor of the cost of your next hire or vendor change.
8. Technical decisions left no trace
Nobody remembers why a given component was chosen or how a given flow works. Without a written record, every past decision must be reconstructed like an archaeological dig before it can be questioned — a permanent tax on every change.
What the debt really costs
Technical debt is paid in three currencies. In money: a growing share of the development budget goes into workarounds, fixes and deciphering existing code rather than new value. In speed: time-to-market stretches while your competitors ship faster. In risk: unpatched vulnerabilities, dependence on key people, inability to absorb business growth. The most insidious part is that this cost remains invisible in the accounts: it hides in inflating estimates and slipping projects. Talented developers also tend to leave codebases where every task is a struggle, which compounds the key-person risk.
How an audit makes the debt visible and prioritisable
A technical audit crosses three perspectives: analysis of the code and architecture (quality, dependencies, security), analysis of the practices (testing, deployment, documentation, access management), and listening to the teams, who almost always know where the problems are. The useful deliverable is not an abstract quality score but a prioritised risk map: what threatens the business in the short term, what slows development down, and the quick wins with the best effort-to-impact ratio. The debt stops being a vague unease and becomes a list of quantified, arbitrable investments that can be defended before the board.
Repaying gradually, without rewriting everything
A full rewrite is rarely the right answer: it is expensive, freezes new features for months and often reproduces the same mistakes. The proven approach is incremental: secure first (backups, critical updates, documentation of vital areas), then clean up the most frequently modified modules as a priority — that is where every euro invested pays back the most — and reserve a share of every project budget, typically around 15 to 20%, for continuous repayment. Within a year or two, the trajectory reverses without ever halting product development. Each repayment should be tied to a measurable outcome, such as faster delivery or fewer incidents, so the effort stays visible.
The hardest part is running this diagnosis calmly while heads-down in daily operations. An outside perspective — from a partner used to auditing SMB systems — brings the method, the comparison with other contexts, and the legitimacy to settle topics that have remained sensitive internally.