Too many BMS installations end as decorative floor plans on a screen nobody opens. The difference between those and a system that pays back is in three things.
Trends that go back far enough
Six months of chiller and AHU data turns a maintenance argument into a measurement. Specify historian capacity at design stage, not after handover.
Alarms that are actionable
An alarm list nobody clears is noise. We tune thresholds after commissioning, during a real occupancy cycle, so the list reflects genuine faults.
Schedules staff can change
If changing an occupancy schedule needs a contractor visit, it will not happen. Operations staff must be able to adjust set points and schedules within safe limits.