I've heard the same thing in regards to creating good credit. I was told you should get a credit card/store card etc. If you can't get one easily then do the prepaid ones that cost like $60 a year to have. Then charge stuff but yes... do the minimum payments, don't pay it off right away. Also, never charge the card to the full balance because that is bad. It's some stupid percentage I've forgotten that helps with your credit, say like only charge 30% of your limit. To me this sounded like you're paying to increase your credit - because you are. You aren't paying off your balance each month, which you are right, you'd think it would look better, but oh no...

Also, I was told every time you get any sort of credit check, via a car place, a bank etc, that also hurts your credit score. If you get multiple checks in a "short" (who knows what they mean by short) period of time that can devastate your credit as well as getting multiple credit cards near each other. Also, apparently if the card offers you an additional credit boost for being a good customer you're only suppose to allow the boost up to a certain dollar amount. Say upgrade from $200 limit to $1000, but not to $1,200. Pay other non credit bills on time... and your income ratio has to be significantly higher than your debt ratio. Like you if have a student loan and pay it on time but still owe $50,000 and only make $30,000 a year that can hurt you.
It's really kooky. I never understood all this. Thankfully? between my ex husband and student loans my credit will be trashed until I die, so I don't have to jump through the credit hoops.
