Audience asks whether each event stores the latest state or the change, and how performance is affected when state must always be computed. Ladd: events represent only what happened, not current state; to get current state you read each event sequentially. Performance countermeasures are readily generalisable — each event has a position exactly one greater than the previous, so entities can be cached tagged with their version and read resumed from the next position. Eventide's entity_store library ships with such a cache and also with snapshotting (periodically writing a representation of current state so a restart doesn't replay millions of events). Disk usage vs storing only current state has its own countermeasures.