What deployment dependencies does an App Builder need to understand when deploying change sets?

Deployment dependencies are metadata components that a component requires in order to be successfully deployed. Salesforce validates dependencies during change set deployment; missing dependencies cause validation failures.
Common dependency chains:
— A custom field's formula references another custom field → both must be in the change set.
— A validation rule references a record type → the record type must already exist in the target org.
— A Flow references a custom object or field → the object/field must exist in target.
— A report type references a custom object → the object must exist.
— An email template references a letterhead → the letterhead must be included.
Resolution strategies:
— Add dependencies to the change set (use "View/Add Dependencies" in the Outbound Change Set).
— Deploy dependencies in a prior change set first.
— Validate the change set against the target before deploying — the validation report identifies missing dependencies without making changes.
Deployment order: Objects before fields, fields before validation rules/formulas, objects before relationships.