Legacy code is code that succeeded long enough to become inconvenient.
Age often signals delivered value and accumulated constraints, not incompetence.
Interpretation
Legacy systems carry the evidence of years: customer exceptions, operational compromises, and rules nobody remembers inventing. Their friction is real, but so is their survival. Approach them as working archives. Understand the value and constraints before judging the form they took.
Practice
- Map business capabilities before technical cleanup.
- Ask operators which failures the system already avoids.
- Change one observable seam at a time.
Anti-pattern
Calling old code worthless before learning who still depends on it.