> * If you write down what happened ("events"), and don't throw away said events, then you can always compare the current state of the system to how you think i

> * If you write down what happened ("events"), and don't throw away said events, then you can always compare the current state of the system to how you think it should be (according to the events). This, by the way, is the fundamental principle of accounting. When you hear “reconciliation” this is what they’re doing - comparing some data reflecting real events against a log of intended events. For example, a nonprofit might reconcile their bank account (actual $ amounts) against GL files generated from their CRM (expected $ amounts.)