The decommissioning costs
In the world of IT, we often categorize costs into two main buckets: capital expenditures (CapEx) and operational expenditures (OpEx). While these two categories are crucial for budgeting and financial planning, there's a third type of cost that often gets overlooked, the decommissioning costs.
Known in the construction industry as DecEx, this cost refers to the expense associated with decommissioning an IT asset. Whether it's a server, a firewall rule, a network link, or any other piece of technology, DepEx is an essential consideration that many organizations forget about until it's too late. In this post, we'll dive into what DepEx is, why it matters, and how to factor it into your IT strategy.
Decex or DePex?
Following the same pattern as CapEx (Capital Expenditure) and OpEx (Operational Expenditure), I would use DepEx.
DepEx cost
DepEx is the cost of shutting things down — not just physically, but in a clean, validated, non-disruptive way. Think of retiring a server, a firewall rule, a network link, a DNS entry, or even a policy buried deep in an access control list. It sounds simple, but it rarely is.
Decommissioning an asset properly usually starts with a bit of detective work. You’ll need to verify documentation (if it exists and is accurate), collect logs, check traffic metrics, and maybe even fire up a packet capture to confirm that the asset is no longer in use. And only then can you safely remove it, hopefully without taking down something critical by accident.
Microsoft uses scream tests to silence its unused servers, Tufin and Palo Alto suggest some tools and procedures for firewall rules.
Zombieland or Scream?
Whatever the technology — on-prem, cloud, networking, security, or applications — the effort and cost of decommissioning must be taken into account. I’ve seen it underestimated far too often, leading to two classic outcomes: either something still in use gets decommissioned by mistake (cue the war room), or some obscure legacy component gets kept alive for years because no one feels confident enough to shut it down. Both are expensive in their own way.
So next time you're planning a new project, migrating a service, or just cleaning up old infrastructure, don’t forget to budget for DepEx. It’s not just a technical task, it’s a financial and operational one too. And if you ever find yourself saying, “We’ll just turn it off and see who screams”, congratulations, you're already paying the price of ignoring DepEx… with interest.
