Legacy technology is often discussed as though age alone makes a system unsuitable. In practice, some old applications are stable, well understood and economically sensible to retain.
Start with business criticality
Understand what the application does, who depends on it and what failure would cost before choosing a technical strategy.
Separate age from risk
An old platform can be low risk while a recently built application can be fragile. Assess maintainability, security, skills and change frequency independently.
Choose the smallest useful intervention
Rehosting, refactoring, replacing components and exposing APIs may deliver most of the benefit without a wholesale rewrite.
