[support] Paypal IPN required ?

Dear All, I am configuring Ubercart with paypal as payment method. While reading online forums I understand that there not need to configure IPN. So my question is how I confirm whether my oder is pending or completed ? As of now my order status (after shopping completed) is Pending. Though customer can received mail with account's details (user/pass) and user can login and can check order status ( which is pending ). If I changed that manually from Pending to Completed then only it assign Roles to the customer. I have tested both payment methods: WPS & Paypal Pro. I am using Drupal 6.22 and ubercart-6.x-2.4.