The federal government covers interest on subsidized federal loans while the student is in school and at certain other times; all other interest is the responsibility of the borrower. (iowastudentloan.org)
To qualify for subsidized federal loans you must meet financial need requirements. (nerdwallet.com)
It used to be that subsidized federal loans almost always came with lower interest rates than private loans, so refinancing didn't make that much sense. (finder.com)