Most people associate the term “legacy system” with old code, but a true legacy system is any application that is difficult to update. A two-year-old app can already be in a legacy state if it’s unscalable.
Many companies put off updating a legacy system, even when they accept its limitations. It can be a hard sell to replace functioning systems, but the longer it is put off, the more expensive it ultimately becomes.
This deck outlines the financial reasons for updating a legacy system.