I had no choice but to finance a car loan at a pretty disgusting rate (14%) thanks to "insufficient credit history" back in the end of September. My credit score was good.
Now it's January; I've been making money, making car payments, and paying bills. I opened a second credit card and did a balance transfer to take advantage of an introductory 0% offer, leaving the first one open to add to my unused credit, and have been paying that each month as well. My credit score is now apparently 742, which is about 100 higher than I remember when I applied (but my memory is untrustworthy).
How long should I wait before attempting to refinance into a lower interest rate on my car loan? How much history will be sufficient?