Leave it alone, on purpose

Every roadmap we deliver contains systems marked LEAVE ALONE, ON PURPOSE, in those words. It is the line clients argue with most and thank us for latest. Not touching a system is a decision, with criteria and paperwork, and it is frequently the highest-return line on the page.

When it is right:

1. The system is stable, cheap to keep, and doing a job that is not changing. A 2012-era app serving a regulatory report that will retire with the regulation in 2029 does not need a rewrite. It needs a decommission date and silence.
2. The migration cost exceeds the remaining lifetime cost. Price the standing stock with a straight face and some moves simply lose the arithmetic: $400k of migration to save $30k a year on a system with four years to live is philanthropy toward your integrator.
3. The risk is asymmetric. Some systems are load-bearing agreements (the shared database being the classic), where the modernization's downside is measured in incidents and the upside in aesthetics.

What "on purpose" requires, so the line survives audit and turnover: a dated one-pager per system. What it is, why it stays, what it costs annually, the conditions that reopen the decision (vendor repricing, volume doubling, the expert retiring), and the containment work that makes staying safe: current backups actually restored once, patches within support, an understudy, monitoring that would notice distress. Leave alone does not mean look away. It means maintain, deliberately, at minimum honest cost.

The market is running a giant experiment on the difference right now. Every SAP ECC shop staring at the 2027 maintenance deadline is choosing between a compressed migration and paying the extended-maintenance premium to stand still a while longer. Standing still at a stated premium, with a reopening date, is a legitimate strategy; standing still by inertia while the consultancy market prices itself into a frenzy is the same posture with none of the protection. The difference is the paperwork, which is to say the difference is whether anyone decided.

The deeper point, learned across every estate we have walked: modernization capacity is the scarcest resource in the building, scarcer than budget. Every system you modernize by reflex spends capacity that the genuinely burning platform needed. LEAVE ALONE, ON PURPOSE is how a roadmap concentrates force. The estates in the best shape five years out are never the ones that touched everything. They are the ones that chose loudly, in writing, and let the boring systems be boring.