The federal student loan system isn’t trying to trick you, but it doesn’t always shout the important part either. When you sign your Master Promissory Note, you agree to a set of rules about interest, repayment, and what happens if life goes sideways. The biggest fork in the road for most undergrads is whether a Direct Loan is subsidized or unsubsidized. Both come from the U.S. Department of Education. Both can be repaid on income-driven plans. Both can lead to forgiveness in the right circumstances. But they are not the same deal. The difference can be thousands of dollars.

Subsidized loans are the better deal if you can get them. They’re for undergraduate students who show financial need, and your school decides how much you can borrow based on your cost of attendance and other aid. The government pays the interest while you’re in school at least half-time, during your six-month grace period after you leave, and during authorized deferment periods. That means your balance doesn’t grow just because you’re still studying or waiting for your first real paycheck. If you borrow $3,500 subsidized and don’t make payments while in school, you still owe $3,500 when repayment starts. Interest that doesn’t accrue is money you keep.

Unsubsidized loans are available to almost everyone, regardless of need. Undergrads, grad students, and professional students can borrow them. That wider access is why so many people end up with unsubsidized debt. The catch is that interest starts building the day the money is disbursed. It doesn’t wait for you to graduate. It doesn’t pause during grace. It doesn’t care that you’re broke. If you don’t pay that interest while you’re in school, it gets capitalized, meaning it’s added to your principal balance. Then future interest is charged on a bigger number. That’s how a $10,000 loan can turn into $12,000 or more before you make a single payment.

Here’s the practical move. If you have both types, pay the unsubsidized loan’s interest while you’re in school if you can afford anything at all. Even $20 a month helps. You’re not required to make payments while enrolled at least half-time, but paying down accruing interest keeps it from capitalizing. Call your loan servicer and tell them you want to make an interest-only payment on your unsubsidized loans. Then check that it was applied to interest, not accidentally scheduled as a regular payment or put toward a different loan. Servicers make mistakes. Your job is to verify.

When repayment starts, don’t panic if you can’t handle the standard ten-year plan. Federal loans offer income-driven repayment plans that cap your payment at a percentage of your discretionary income. If your income is low, your payment can be as low as zero. That counts as an on-time payment for forgiveness purposes on many plans. Subsidized and unsubsidized Direct Loans are both eligible for income-driven repayment, Public Service Loan Forgiveness, and teacher loan forgiveness in certain cases. But forgiveness is a long game with strict rules. Document everything. Recertify your income every year. Don’t assume your servicer will do it for you.

Also know what you’re not dealing with. Federal loans have fixed interest rates, flexible repayment, death and disability discharge, and borrower defenses that private loans usually don’t. If you’re choosing between a federal unsubsidized loan and a private loan, the federal loan is almost always the safer bet, even with accruing interest. Private loans may look cheaper on the rate, but they often lack the safety nets. They can require a cosigner, have variable rates, and offer far fewer ways out if you lose your job or get sick.

The smartest approach is boring but effective. Max out subsidized loans first, since they’re need-based and don’t accrue interest while you’re in school. Take unsubsidized loans only for what you truly need, not for lifestyle upgrades. Pay accruing interest when you can. Choose an income-driven plan if your first job doesn’t cover the standard payment. And never ignore your servicer. Open the mail, log in, and check your balance. Federal student loans are manageable, but only if you know which type you have and what it’s doing while you sleep.