Incorrect (always fetches fresh data):

// app/routes/post.js
import Route from '@ember/routing/route';
import { service } from '@ember/service';

export default class PostRoute extends Route {
  @service store;

  model(params) {
    // Always makes API call, even if we just loaded this post
    return this.store.request({ url: `/posts/${params.post_id}` });
  }
}