మీరు ఎప్పుడు పాత వ్యవస్థను పునర్నిర్మించాలి, భర్తీ చేయాలి లేదా పేంషన్ చేయాలి?

REFACTOR (improve in place) when:
  - Core logic is sound; it's holding business value
  - Problems are localized; you can improve incrementally

REPLACE (rewrite/migrate) when:
  - It blocks important work and can't be incrementally fixed
  - Maintenance cost > rebuild cost over a sensible horizon
  - It's a growing security or reliability liability

RETIRE (remove entirely) when:
  - Its value no longer justifies any maintenance cost
  - Usage has dwindled; a simpler path exists