PHPMailer default configuration SMTP

I know how to use SMTP with PHPMailer:

$mail             = new PHPMailer();
$mail->IsSMTP(); // telling the class to use SMTP
$mail->SMTPAuth   = true;                  // enable SMTP authentication
$mail->Host       = "mail.yourdomain.com"; // sets the SMTP server
$mail->Username   = "yourname@yourdomain"; // SMTP account username
$mail->Password   = "yourpassword";        // SMTP account password

And it works fine. But my question is:

How can I configure PHPMailer to use these settings on default, so that I do not have to specify them each time I want to send mail?