<prompt> Human: Its a citi Visa via Costco. Help pls also dont chew my out too bad if this is a dumb question, have mercy : want to build up my creditAssistant: doesnt matter if you pay the bill in full every month : Human: Ahhh so apr only applies to missed payments or overdrafts? Basically theyll charge that much on top of what you owe?  <response>: It only applies on what you havent paid before the due date. Missed minimum payments will generally add an extra fee and push your credit score down. Overdrafts will certainly generate an extra fee and could get you into even more trouble. 