Application Portfolio Management
also called APM, Application Rationalisation
Maintaining an inventory of every application with its owner, cost, business value and technical health, and using it to decide what to invest in, replace or retire.
Most large estates do not have a reliable list of their own applications, which makes every modernisation decision a guess.
The minimum viable record per application: owner, business capability supported, annual run cost, user count, technical health (supportability, security posture, dependency currency), and business criticality. From those, the standard analysis is a grid of business value against technical health: high value and poor health means invest or replace; low value and poor health means retire; low value and good health means leave alone.
The consistent finding is that a meaningful fraction of an estate is retirable — superseded, barely used, or duplicated — and retirement is the highest-return action available, because it removes run cost, licence cost, security surface and support burden simultaneously.