Working With Legacy Code: Making Steady Progress Without Breaking Things
February 22, 2024
I’ve worked on a lot of legacy systems. Some were written ten years ago, with little test coverage and unclear logic. At first, it was frustrating. But I learned to slow down, read the code, and ask questions before changing anything. You can’t rush fixes in a system you don’t fully understand.
Now I look for ways to make things a little better each time I touch them. I might add a test, clean up a method, or write down how something works. Over time, the system becomes easier to change. It’s not flashy work, but it helps the team move faster and with more confidence. I think that’s what good engineering is.
I don’t always get to write fresh code. That’s fine. Most systems live a long time. If you want to be helpful on a team, you have to get good at reading, debugging, and changing old code without breaking things. That’s where I try to add value; by making things a little clearer for whoever comes next.
Will McCracken
Will McCracken is a seasoned fullstack engineer with 8+ years of experience in Ruby, JavaScript, and DevOps. He's worked on e-discovery platforms, job queue orchestration, and infrastructure automation. Will's writing distills technical challenges into readable reflections, with an emphasis on simplicity, observability, and trade-off thinking.