Just signed up for auto pay (for the free hd), and I read where credit cards are billed when the billing date is reached, and the debit card is billed a few days prior to the Due date. Unfortunately, I found that to be incorrect, as my Paypal debit card was charged on the billing date. I called D* and was told there is no rule that debit cards are charged "a few days prior to due date". The CSR stated it may occur with some accounts, but is not specifically true with all billing. So be aware, signing up for debit card auto pay, may generate immediate payment on the billing date for your account.