Use static variables


When the situazion allows it, use static variables to avoid running the same code several times. You will thus prevent unnecessary CPU usage.
This is especially effective for resource-intensive procedures.

To only load a heavy-to-load parser once, use static variables:

private function dataParserLoad() { 
    static $done = FALSE;
    if (!$done) {
      require_once APPLICATION_PATH_APP . '/ libraries/DataParser/Parser.php';
      $this->parser = new DataParser();
      $done = TRUE;