Where do you place common methods that you use throughout your module

Question

I have a method that is going to be called in multiple files in my module:

public function getStore(){
         $order = Mage::registry('current_order');        
         $store_id = $order->getdata("store_id");
         switch ($store_id){
             case "2":
                $store = "DE";
                break;
             case "3":
                $store = "US";
                break;
             case "9":
                $store = "HG";
                break;
             case "1":
                $store = "DK";
                break;
             default:
                $store = "ES";
                break;
         }
    return $store;
}

What is the magento way to deal with this methods?

Thanks!

Answer 1

In a helper is the normal place. Sometimes you see these kinds of methods in models as well (i.e. Mage_Core_Model_Date) but I tend to stick to just helpers.