All software eventually becomes legacy code.
Technologies become obsolete and no longer support modern development.
Code bases become unwieldy and no longer support current business needs.
Business needs shift and software doesn't always keep up.
You wonder if the software is causing more problems than it creates.
Many applications can be modernized without undergoing an entire rewrite from scratch.
Through large-scale refactoring, and technology upgrades, applications can pivot from liability to asset.