A growing number of lenders are offering to convert borrowers’ existing federal or private student loans into a new loan with a potentially lower interest rate.

Personal loan lender Earnest Operations and Navy Federal Credit Union began refinancing student loans this year.

Borrowers who don’t meet this criteria are generally better off sticking with their existing loans, especially if they are federal loans since they provide more repayment plans for those experiencing financial difficulties.

Darien Rowayton Bank’s range runs from 1.9% to 4.5% for variable-rate loans and 3.5% to 6.25% for fixed-rate loans.

Switching from a federal loan to a private loan makes most sense for borrowers who have high credit scores and are in occupations with low unemployment and high incomes.

Federal borrowers can qualify to have their monthly loan payments lowered to 10% to 15% of their discretionary income-an advantage for borrowers who graduate with a lot of debt and a low salary.

Borrowers with such jobs or those in low-paying positions, high debt levels, or who are worried they might encounter financial difficulties at some point should stick with federal loans.