Technical Debt: When to Pay It Off and When to Live With It
Technical debt is a concept known by almost every software development team. Just like financial debt, technical debt increase over time, making the codebase more and more difficult and expensive to maintain.
This article explores the nuances of technical debt management, focusing specifically on when you should prioritize paying it down and when it might be reasonable to live with it. We'll examine concrete indicators, practical strategies, and real-world scenarios that can help development teams make informed decisions about their technical debt.
TL;DRβ
Technical debt is like any other debt: it's not necessarily bad, but might become dangerous if ignored. You should accept it wisely, track it clearly, and pay it off when the cost of keeping exceed the benefit.
In other words: write fast but refactor smart.
Understanding Technical Debtβ
Before diving into management strategies, it's important to understand that technical debt can take multiple forms.
Code-level debtβ
Suboptimal code patterns, duplicate code, violations of best practices...
Example: code duplication
function checkUserEmail(email) {
return /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email);
}
function validateAdminEmail(email) {
const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/; // Duplicated logic
return emailRegex.test(email);
}
β¬οΈ
// Better approach would be:
function validateEmail(email) {
return /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email);
}
Architectural debtβ
Structural issues that affect the entire system, such as tight coupling between components or monolithic architectures that should be modular.
Documentation debtβ
Missing, outdated, or inadequate documentation.
Test debtβ
Non-sufficient test coverage, or overly complex test suites.
Infrastructure debtβ
Outdated dependencies, deployment processes, or development environments.
Technical debt is inevitable in most software projects. The key ain't to eliminate it entirely (that obviously not possible in the real world) but to manage it strategically.
When to Pay Off Technical Debtβ
When It Directly Impacts User Experienceβ
If technical debt is causing visible issues for end users, such as slow performances, frequent crashes, or security vulnerabilities it should be addressed immediately. Those issues directly affect your product's reputation and user experience.
Example: Performance debt affecting user experience
// Before: Inefficient API calls causing lag
async function loadDashboard() {
const userData = await fetchUserData(); // 500ms
const statsData = await fetchStatsData(); // 700ms
const notifData = await fetchNotifData(); // 600ms
// Total: ~1800ms (sequential calls)
renderDashboard(userData, statsData, notifData);
}
β¬οΈ
// After: Optimized parallel API calls
async function loadDashboard() {
const [userData, statsData, notifData] = await Promise.all([
fetchUserData(),
fetchStatsData(),
fetchNotifData()
]);
// Total: ~700ms (parallel calls)
renderDashboard(userData, statsData, notifData);
}
When Development Velocity Is Decreasingβ
If your team is spending more time working around issues in the codebase than adding new features, it's a clear sign that technical debt is hampering productivity. Track these metrics over time:
- Time spent on bug fixes vs. new feature development
- Average time to implement new features
- Frequency of unexpected issues during deployment
When these metrics show a negative trend, it's the time to allocate resources to paying down debt.
When Adding New Features Suddenly Becomes Excessively Complexβ
If seemingly simple features require disproportionate effort due to the complexity of the codebase, technical debt is likely the culprit. This is particularly evident when:
- Simple changes require modifications in multiple places
- Adding new functionality requires extensive understanding of unrelated parts of the system
- Developers consistently underestimate the time required for new features (Trust me, whether youβve been coding since floppy disks or the cloud was just literal water vapor, your estimates will still be hilariously wrong)
When Onboarding New Team Members/Interns Takes Too Longβ
If new developers struggle to understand the codebase and are able to contribute and fix issues in a reasonable time, it could indicate excessive technical debt. Don't understimate the power of a clean, well-structured codebase with appropriate documentation. It will accelerate onboarding and reduce the learning curve exponentially.
You Are Scalingβ
What worked for 100 users may fall apart at 1000. Scalability is one of the top reasons to pay off infrastructure or architectural debt.
When to Live With Technical Debtβ
When Time-to-Market Is Criticalβ
In highly competitive markets or when working against tight deadlines, accepting some technical debt might be necessary to ship products on time. This is especially true for startups or new products where market validation is far more important than perfect code.
Example: Expedient MVP implementation with acknowledged debt
/*
TODO: Technical Debt - Current Implementation
This is a simplified implementation to meet the MVP launch deadline.
Known limitations:
- No caching mechanism (could cause performance issues at scale)
- In-memory storage (will need DB implementation for production)
- No error handling for network failures
*/
async function fetchProducts() {
// Simplified implementation for MVP
let products = {};
const response = await fetch('/api/products');
const data = await response.json();
data.forEach(item => {
products[item.id] = item;
});
return Object.values(products);
}
When the Code Is in a Rarely Changed Areaβ
Not all parts of a codebase are created equal. Some modules or components rarely change after initial development. Technical debt in these stable areas might not be worth addressing if they work correctly and don't affect the rest of the system.
When the Cost of Fixing Exceeds the Benefitsβ
Sometimes, the effort required to fix technical debt outweighs the benefits. This is particularly true for:
- Legacy systems approaching retirement
- Code that will soon be replaced by a new implementation
- Non-critical features with limited usage
When Technical Debt Is Isolatedβ
If the technical debt is well-contained and doesn't affect other parts of the system, it might be acceptable to live with it (it will not be the end of the world).
When Your Team Is Undergoing Significant Changesβ
During periods like team transitions, onboarding multiple new members, or dealing with organizational restructuring, maintaining stability might be more important than paying down technical debt. Wait for a period of team stability before tackling significant refactoring efforts.
Practical Strategies for Technical Debt Managementβ
Allocate Regular Time for Debt Reductionβ
Many successful development teams allocate a fixed percentage of their time (e.g., 20%) to addressing technical debt. This creates a sustainable approach to debt management without sacrificing feature development.
Practice Continuous Refactoringβ
Instead of large, risky refactoring, incorporate continuous refactoring into your development workflow. This reduces the risk and makes debt reduction more manageable.
Documentationβ
Use TODOs, comments, or issue trackers to record what was done and why. Donβt let debt hide.
Measuring the Impact of Technical Debtβ
To make informed decisions about technical debt, you need to measure its impact. Here are concrete metrics to track:
Development Velocityβ
Track how long it takes to implement similar features over time.
Code Churnβ
Measure how frequently code changes in specific areas.
Build and Deployment Metricsβ
Track build failures, deployment issues, and rollbacks.
Static Analysis Resultsβ
Use tools in your pipelines workflow like Ruff, Bandit, or ESLint to identify code quality issues.
Real-World Case Studiesβ
Case Study 1: Etsy's Continuous Deployment Revolutionβ
Etsy faced significant technical debt in their deployment process, with infrequent, painful deployments that slowed innovation. Instead of a massive overhaul, they gradually transformed their process:
- They introduced automated testing and continuous integration
- They focused on small, incremental improvements to their deployment pipeline
- They built tools to increase visibility into the deployment process
This gradual approach allowed them to move from deployments every few weeks to multiple deployments per day, without disrupting their business operations.
Case Study 2: Twitter's Rewrite of Their Timeline Serviceβ
Twitter's timeline (a.k.a X now) service accumulated significant technical debt as the platform grew. They decided to rewrite it completely, but did so incrementally:
- They built the new system alongside the old one
- They gradually moved traffic to the new system
- They maintained backward compatibility throughout the transition
This approach allowed them to replace a critical service without disrupting the user experience.
Conclusionβ
To conclude, the most successful approach to technical debt management is usually a balanced one: allocate regular time for debt reduction, establish clear metrics for tracking debt, and build a culture that values code quality alongside feature delivery.
Remember that the goal ain't getting the perfect code, but a codebase that enables your team to deliver value to users efficiently and sustainably. By making informed decisions about when to pay off technical debt and when to live with it, you can strike the right balance between speed and sustainability in your development process.
References and Further Readingβ
- Martin Fowler - "Technical Debt"
- Martin Fowler - "Technical Debt Quadrant"
- Attlassian - "Say bye to tech debt: Agile solutions for clean development"
- thoughtworks - "How to overcome tech debt and keep your business moving"
- thoughtworks - "Tech debt β what business leaders need to know"
- Etsy.com - Blameless PostMortems and a Just Culture
- blog.x.com - The Infrastructure Behind Twitter: Scale
- blog.x.com - Manhattan, our real-time, multi-tenant distributed database for Twitter scale