Property Sourcing is an anti-pattern in Event Sourcing where developers model events around individual field changes (e.g., FirstNameChanged, LastNameChanged) rather than meaningful business operations. This leads to many tiny, copy-pasted events with no business value that are hard to manage and consume. The recommended approach is to group related field changes into business-meaningful events like PersonalDataUpdated, using Option types to indicate which fields were actually changed. Events should reflect the outcome of business operations, not data model mutations. Exceptions exist for fields that carry genuine business significance and can trigger workflows, such as EmailUpdated or AccountBalanceUpdated.
