Split Large Models by Domain Responsibility

As a model such as Subscription grows, its behavior becomes harder to find and understand. Traits can group cohesive responsibilities such as notifications or transactions, or well-defined sets such as relationships, queries, state checks, and actions.

Prefer divisions based on domain meaning rather than file length alone. Names such as NotifiesSubscriptionEvents or ManagesSubscriptionLifecycle explain why the methods belong together. If a team adopts consistent groups such as Scopes and Relations, apply them clearly without turning a generic Helpers trait into a home for unrelated logic.

A trait is an organization and composition tool, not an independent architectural boundary. Behavior that coordinates several entities, integrations, or major side effects may belong in an action, service, or domain object instead. Watch for hidden dependencies and name collisions, and test behavior through the model's public interface.