Lazy loading retrieves a relationship only when code first accesses it on a model, such as reading $post->comments. It is convenient for isolated records, but accessing the same relationship inside a loop can cause many additional database queries.

Eager loading retrieves relationships up front with methods such as with when the main query runs. It normally uses a small, predictable number of queries and is the preferred approach when a response or view knows it will need related data for many models. The appropriate choice depends on what data the operation truly needs.