Why the old system is still running
The new one went live eighteen months ago and the invoice has not changed. There are usually four reasons and only one of them is technical.
Four reasons
Nobody owns the ending
The program that built the replacement closed, and its budget closed with it. Retirement was inside its scope rather than after it, so when the program ended the retirement ended too — not canceled, just orphaned. There is no line in anybody's objectives that says the old thing is off.
Somebody is still reading from it
Usually one or two consumers nobody knew about: a report that runs monthly, a downstream team that built an integration without telling anybody, a regulator return assembled by hand from an extract. Each is small. Each is enough to keep the whole system powered.
The records question was never asked
Somebody raises retention late, legal quite properly says they cannot approve a deletion they have not reviewed, and the review needs a person who is not available until next quarter. The system stays on, indefinitely, in a state everyone describes as temporary.
It genuinely cannot be turned off yet
The honest one, and the rarest. Sometimes a dependency is real and the work to remove it is larger than the saving. This gets the least space here because it is the least common, and because it is the reason most often given for the other three.
Why it is never anybody's job
Retirement is scoped as a task, not an engagement
It appears as a line item at the end of a plan, unestimated, owned by whoever is left. Work described that way does not get done — not because people are lazy, but because a task with no owner and no date loses every contest against work that has both.
Nobody is promoted for it
There is no launch. There is no demo. The best possible outcome is that nothing happens and a number gets smaller, and the person who made it happen has produced no artifact anybody can look at.
Every estate we assess has at least one system whose only remaining function is to be difficult to turn off.
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— Owen Marchetti-Sund, Principal, Decommissioning
Scoping it as its own thing
A switch-off date
Not a target. A date, named person, in a plan, with the consequences of missing it written down. Everything else in this list is downstream of somebody being willing to commit to one.
The retention schedule, first
Before extraction, before archive design, before anybody touches a server. Which records carry an obligation, for how long, signed by somebody in legal who has actually read it. Asked at the start this costs three weeks; asked at the end it costs a quarter.
Starve, do not cut
Reduce traffic in stages and watch. The system stays warm and recoverable for a window of six to twenty weeks, and roughly one program in three sees an unexpected consumer appear in that window. That is precisely what the window is for, and it is the reason cutting rather than starving is how decommissioning acquires its reputation.
