Technical Debt and Ageing Systems

When developers take shotcuts or decrease the quality to gain time, they will cause a technical debt. By doing nothing and letting the system age, the technical debt is growing too. Actually, as soon as we’ve implemented the code, it starts to age.

The code that is tightly connected to a specific technology ages more than code that is written purely in its own, e.g. business logic. But sometimes it is the language itself that is ageing. Or rather, it’s impossible to separate the code itself from the infrastructure.

Developers’ view

Developers often use the term technical debt to describe what happens when they are forced to implement a design that will decrease code maintainability. Let’s say it takes three weeks to develop something properly, but because of time pressure they have to do a bad design that take two weeks instead. Later on, when the feature is in production and there might have been more changes to it, it would take them 3 weeks to refactor.

DevelopmentGood design Shortcut
Develop feature3 weeks2 weeks
Refactor to reduce technical debt3 weeks
Total3 weeks5 weeks
Technical debt example

By making a lot of shortcuts, the technical debt grows and there will be a future cost to make the code maintainable. Changes will take longer and there is a higher risk for defects.

Technical debt is the coding you must do tomorrow because you took a shortcut in order to deliver the software today.

Technical Debt: The Ultimate Guide

Ageing systems

I would like to widen the definition a bit. When building new software there is a lot of focus on features. This is necessary to get more customers and take market shares. There are also technical and architectural decisions about how to fulfil non-functional requirements like scalability and maintainability. All systems have been through this process, even the old ones. Decisions have been made based on what was available and popular at that time.

As the world change, your system will age. It might not keep up with new requirements when it comes to performance, scalability and usability. I consider this a technical debt as well, since it means that you, by doing nothing, push a growing cost to the future.

What problems does technical debt cause in ageing systems?

What will happen when you let your system age:

  • Users are limited when using the system. Your system can’t be used on a wide range of devices or operating systems. The system can’t take advantage of new technology and frameworks provided for, e.g., browsers, which might allow only a very basic user experience.
  • The system can’t scale. The technology does not support scaling or performance requirements. Maybe you use technology that can’t be moved to the cloud.
  • Unable to improve business model. The technology does not support the business model you want to implement. For example, you install the system on each customer’s site, but you actually want to offer a SaaS (Software as a Service).
  • Code changes take time and are costly. The code base has grown large without refactoring and time to delivery is huge for each change.
  • Lack of development resources. It’s hard to find developers that want to work with old technology.

How should companies handle the technical debt?

What happens if the company doesn’t handle the technical debt? Probably not so much, until it’s too late, which might take many years. As long as the competitors have a similar technical debt the company can be successful. But if you can’t run your system in the cloud, and suddenly a competitor launches a new SaaS solution, you might find yourself in a very difficult situation.

A company must fund money to handle the technical debt. The debt is a loan from the future, that will need to be paid back. An alternative is of course to continuously evolve the business and find other ways to earn money, and after that scrap the old solutions. The nature of a technical debt is that it can never be fully paid, just kept at a reasonable level. To find that level, the management have to weight different factors like competitors, risk, finance etc.

There is no simple answer to the question about how to handle technical debt. But a general advice would be to admit that it exists, and to take informed decisions. It is a much lower risk to spread out the investments over many years, doing stepwise improvements, rather than doing nothing for twenty years and then perform a complete rewrite of the whole system.

Conclusion

The technical debt is very unlikely to ever be fully paid off. It can be higher or lower, and have more or less implications on the company. Defining the amount of the technical debt is a strategic decision that has to weigh in knowledge about technology, market and finance.

Knowledge about this is usually spread over different roles in a company, and people tend to have little understanding beyond their own areas of expertise. Awareness and discussions will significantly increase the chances for a company to successfully handle their technical debt.

https://martinfowler.com/bliki/TechnicalDebt.html