Operations and Maintenance.
Operations inherits the controls dataset on day one and lives with it for 20 to 40 years. Drawings revise on a different cadence than the plant, and the master P&ID set drifts from the installed reality unless something keeps them aligned.
Use it through the lifecycle.
P&ID drift from installed reality is the standing risk in long-term operations. A structured re-baseline off the current drawing set, diffed against the prior record, produces the MOC change report and the updated SIS scope that PSM and IEC 61511 audits require.