Aging Experts, Not Technology, Are the Real Risk Behind Legacy System Failures

A department's 1998 financial application remains in production because four ageing specialists — averaging 56 years old — hold decades of undocumented institutional knowledge about why its roughly 900 customisations exist. Two of those experts have informally signalled they plan to retire within three to four years, creating a knowledge-loss deadline that no formal project plan acknowledges. The problem is compounded on the vendor side, where only two engineers can handle complex support queries and both are nearing the end of their careers. In response, the organisation has permanently paired younger engineers with the legacy system, is documenting each customisation by risk priority, and is paying above market rates to retain critical expertise. The author argues that the true barrier to modernising legacy estates is neither technology nor budget, but a handful of irreplaceable people whose departure timeline is rarely factored into planning.