Let's say we separate the product list into a file named productlist.tpl. This because we are lazy and don't want to write/modify the same code into category.tpl, manufacturer_info.tpl, search.tpl and special.tpl

Then we normally would just do:

        require_once('productlist.tpl');

But then if there is modifications added to it, it would not load the modified version from system folder. Thus I wonder if this is the best way, or is it any better I don't know:

        if (file_exists(DIR_MODIFICATION . '/catalog/view/theme/' . $this->config->get('config_template') .'/template/product/productlist.tpl')) {

            require_once(DIR_MODIFICATION . '/catalog/view/theme/' . $this->config->get('config_template') .'/template/product/productlist.tpl');

        } else {

            require_once('productlist.tpl');

        }