You can unguard all your Models instead of setting the protected guarded variable to an empty array in each App\Models\YourModel class using Model::unguard() in the boot method of AppServiceProvider class.
<?php
namespace App\Providers;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Support\ServiceProvider;
class AppServiceProvider extends ServiceProvider
{
/**
* Bootstrap any application services.
*
* @return void
*/
public function boot(){
Model::unguard();
}
}