When your codebase becomes a museum
Every layer of a long-lived codebase tells a story. The problem is the docents have all left, and visitors keep tripping on the exhibits.
Most codebases more than three years old have a museum quality to them: distinct architectural periods, each with its own conventions, none of them entirely current. The current team inherits the whole collection.
The exhibits are still load-bearing
Unlike a real museum, you can't just rope off the medieval wing. The old code is doing work — often the work most critical to revenue. Touch it carelessly and it crumbles. Leave it alone and onboarding doubles.
Curate, don't restore
Pick the exhibits worth modernizing. Label the rest. Add tour signs (READMEs, ADRs, ownership tags) so the next engineer doesn't have to reverse-engineer history. You're a curator now, not a renovator.
The best long-lived codebases aren't pristine — they're well-labeled.