1. Duration of 0% APR on balance transfer. This can be as short as 5 months or as long as 21 months depending on the issuer. Of course, the longer the duration, the better for the credit cardholder. Note that after the promo period, the APR reverts to the normal rate. And in the event that the cardholder is remiss in his payment, the penalty may be the revocation of the 0% APR offer with corresponding penalties to boot. So if you decide to avail of this offer, make sure that you pay on time.