When migrating aura components to LWC, a developer should consider two guidelines: migrate one component and then determine whether additional effort would make sense and start with simple components that only render UI. Migrating one component and then determining whether additional effort would make sense allows the developer to evaluate the benefits and costs of migration and decide whether to continue or stop. Migrating simple components that only render UI allows the developer to leverage the performance and modern features of LWC without much complexity or dependency on other components or services. Starting with migrating trees of components (components within components) is not a good guideline, as it can introduce more challenges and dependencies that can complicate the migration process. Forcing all developers to write any new components using Lightning web components is not a good guideline either, as it can create inconsistency and confusion among developers and users. Salesforce References: [Lightning Web Components Developer Guide: Migrate Aura Components to Lightning Web Components], [Lightning Web Components Developer Guide: Migration Considerations]