Universal Containers needs to stamp the Stage_Last_Changed__c date field on the Opportunity record whenever StageName...

A before-save record-triggered flow is optimized for updating fields on the same record that initiated the automation. The flow can trigger when an Opportunity is updated, test whether StageName changed, and assign the current date directly to Stage_Last_Changed__c . Salesforce recommends before-save flows for updating fields on new or changed triggering records because the changes are applied before the database save and avoid an additional DML operation. Salesforce also confirms that values assigned to the triggering $Record are automatically persisted. A scheduled path would introduce an unnecessary delay, while an approval process does not fit a simple field-stamping requirement. An autolaunched flow invoked manually would depend on user action and therefore could not reliably guarantee that every Stage change is captured.

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