The N+1 query is the silent killer of Laravel apps. with('relationship') eager-loads in one extra query; with('post.author') chains across hops.
For ‘select only what you need’ use with(['posts:id,title']) — note that you must include the foreign key for the relationship to hydrate correctly.
Telescope or Debugbar’s query timeline will surface N+1 issues fast. Long term, enable strict mode globally via Model::preventLazyLoading() in non-production environments.