As Rails enters its tweens, “legacy Rails” projects are increasingly common. Even if you haven’t dealt with such projects, every line of code we leave in production is destined to become legacy code. As developers, our everyday decisions make it easier or harder to work in a codebase over time. I’ll share some of the decisions, both wise and unwise, that I’ve made or encountered in five years of working with aged Rails codebases. With just a bit of forethought, your Rails projects won’t be “aged” or “legacy” - they’ll be timeless.