Im 18 (turning 19 in a few weeks) and ive had my credit limit raised on one from 1100 to 2000 and ive never taken more than a month or two (latest) to pay off balances. I agree that making more payments raises your credit, but its a tradeoff with paying interest (unless you have 0%) and getting too confortable with low payments until you have one big bill.
-ivan c.
