I think I know what you're talking about, but not exactly. Could you please elaborate a little bit further with more examples?

I'm worried about interacting directly with Models - as Repositories are supposed to extract the DB layer from Controllers

Say I have:

class User extends Eloquent {
     public $name;
     public $email;

    //...

    public function roles() {
        // return array of roles
    }

    public function addRole($role) {
        // add a new role
    }

    public function posts() {
        // return array of posts
    }

}

The addRole() and roles() function interacts with another Eloquent class to create a record.

But now I want to migrate the Users and Roles to MongoDB. In theory the code contained within the User model could change drastically and cause a few bugs. If I have bind the model to an interface it at least assures the right functions are available.

If I've got concrete functionality connected to the User like addRole() - should that go through a Repository or separate Application Service?

Should I also be worried about exposing 'getters'? The call $user->get('email') could change when updating schema - what's the best practice to defend against that?

Another example, say I'm updating a field the code behind it could be different if I'm using NoSQL vs MySQL so should I worry about exposing methods through the Model and opt for updating in the repository instead?

ie: $user->set('name', 'Adam')

or $user_repository->update($id, ['name' => 'Adam']);

Right now the repository would call the $user->set() method in a roundabout way but there is some protection there.

Has anyone got any advice on this one for me?