In deciding which student loans to pay off first, consider factors such as loan type, interest rates, and repayment terms. There's no universal answer.

Credit scores could drop by more than 150 points for some borrowers and will likely result in "reduced credit limits, higher interest rates for new loans and overall lower credit access" for affected borrowers, according to a Federal Reserve Bank of New York report posted Tuesday.

The more than 9 million student loan borrowers who are estimated to be past-due could experience "significant drops" in their credit scores, the Fed warns.