The Hidden Costs of Technical Debt in Rails: Lessons from Client Projects

When people hear the phrase “technical debt”, they often picture broken code, outdated infrastructure, or a total rewrite waiting to happen. But in our experience at Planet Argon opens a new window , technical debt usually shows up more quietly.

It’s not a crisis. It’s a pattern.

It shows up in how long it takes to make changes, how often bugs sneak in, and how hesitant developers are to touch certain parts of the codebase. And while it rarely announces itself, it always costs something — whether in time, budget, or momentum.

In this post, we’ll highlight real-world examples of how technical debt has surfaced in Rails applications we’ve worked on. These aren’t horror stories — they’re common issues we see even in well-run projects. More importantly, we’ll share some ways teams can manage debt strategically without a massive rewrite.

Case 1: When Code Keeps Piling Up in the Same Place

In one Rails project, we noticed a subtle form of technical debt that had built up gradually. The application served multiple user types — patients, providers, business partners, and administrators—each with their own interface and logic. The development team had done a solid job using namespacing to keep these contexts distinct.

However, some controller files had grown large within each namespace, especially the dashboard controllers. These handled a wide range of user actions from a single entry point, which made sense from a UI standpoint, but introduced some issues:

• It became harder to locate and update specific functionality.
• Callback logic grew more complex and more challenging to follow.
• Onboarding new developers required more time to navigate through large, multi-purpose files.

The team wasn’t doing anything wrong — they had smart strategies in place — but as the product grew, the structure was starting to show strain.

We recommended a few practical improvements:

• Break up larger controllers into smaller, focused components.
• Consider isolating feature-specific logic in its own controller.
• Review callback patterns for opportunities to simplify or standardize.

Takeaway: Even with good organization, controller logic opens a new window can accumulate in ways that slow teams down. Proactively restructuring large files improves clarity, supports onboarding, and makes managing future development easier.

Case 2: Outdated Dependencies Block Growth

Another client came to us with a clear goal: modernize their e-commerce experience. They wanted to expand shipping options, introduce a new payment provider, and upgrade their Rails version in the process.

It seemed straightforward — until we looked under the hood.

The application relied on an older version of Spree opens a new window , which in turn depended on a gem called spree_active_shipping. That gem had not kept pace with Rails or Ruby upgrades and depended on active_shipping, a legacy library no longer maintained by Shopify.

Here’s what happened:

• Bundler couldn’t resolve dependencies unless we removed spree_active_shipping
• But the app couldn’t boot without it — too many references across the codebase
• We initially tried forking and updating the gem, removing unsupported carriers like UPS
• Eventually, we determined it was more effective to replace the integration with a custom-built shipping function that was simpler and easier to maintain

What began as a routine upgrade became a multi-step project to unwind and replace legacy code that had quietly become a blocker.

Takeaway: Even a small, outdated gem can slow your ability to adapt. Modernizing isn’t always about rewriting opens a new window — it’s about identifying the pieces that no longer serve you and building something leaner in their place.

Other Common Signs of Technical Debt

Beyond these two examples, here are a few patterns we regularly see in long-running Rails apps:

• Code clumping: New logic gets added to existing files simply because “it’s already there.” Over time, those files become harder to navigate.
• Silenced tests: Developers comment out tests to meet a deadline, promising to clean them up later, but rarely come back. The test suite loses integrity.
• Unclear ownership: If no one feels confident making changes in certain parts of the codebase, that’s often a sign of hidden complexity.
• Stretched estimates: When developers hesitate to give timelines, it’s often because they know the area in question is fragile or hard to follow.

None of these issues feel dramatic in isolation, but they compound over time, slowing down your team and increasing the risk with every release.

What You Can Do Without Rewriting Everything

Managing technical debt doesn’t require a fresh start. In fact, we’ve found that small, consistent changes are often the most effective:

• Refactor as you go: Let developers tidy up logic when working in an area, not just during “refactor sprints.”
• Clean up your test suite: Prioritize fixing or removing commented-out or flaky tests. It builds trust in the pipeline.
• Audit controller patterns: Look for overly large files or inconsistent structures that confuse new team members.
• Review your dependencies: Outdated gems can be upgraded incrementally or replaced when the time is right.
• Make structural clarity part of onboarding: Ask new devs what confused them — it’s usually where cleanup is most needed.

A few hours of codebase analysis or dependency review can surface the next few months of improvement work.

Wrapping Up

Technical debt doesn’t mean your Rails app is broken — it just means it’s aging. That’s not a failure. It’s a sign that your team has been building and adapting over time.

But the longer it goes unaddressed, the more it starts to cost you: in time, bugs, developer morale, and missed opportunities. The best teams aren’t debt-free; they’re just intentional about how they manage it opens a new window .

Understanding how technical debt accumulates — and how it quietly affects your team’s momentum — is the first step toward making smarter, more sustainable decisions for your codebase.