Many college students leave college with a huge debt that takes decades to pay off. Credit cards are one of the many ways that students can get into trouble, since often it seems like “free money” and they don’t realize that what is spent still has to be paid off.

According to CNN Money, college students in the class of 2013 graduated with an average debt of $35,200 of which $3,000 was credit card debt. After graduating and realizing how much debt they had accumulated, 39 percent said that would have done things differently while in school to save money, receive more aid, or spend less. This was up from 25% in 2011.

The best advice for students is to keep track of their finances and not spend any more with a credit card than they would with cash or a debit card. Nothing is free, so while a credit card makes spending seem more theoretical, it can cause students to rack up debt quickly.

Being responsible with a credit card is also more than just spending a reasonable amount that you can afford, but also paying off the entire amount that you spend – not just the minimum payment. Many college students don’t realize that that they should pay off the full amount that they spend each month and that just covering the minimum payment isn’t getting out of paying the rest later.

Depending on the credit card company, the interest rate for an unpaid balance may vary, but if not paid off quickly that interest will add up quicker than many people realize. It can take years longer to pay off a small debt.

If you have too much debt on your credit card and can’t afford to pay off the full amount, it is always advisable to pay more than the minimum payment. Even if it’s only a dollar more, it can make a huge difference in the total amount you end up paying and the amount of time it takes to pay off the total debt. If only paying the minimum amount due, the debt will just keep growing at an increasing rate because of interest due.

For students who have trouble keeping themselves in check with their spending, it can help to just use your credit card once every couple of weeks for a purchase so that it is still possible to build good credit but the rest of the time use cash from a bank account. It is much harder to spend money when you’re giving away cash in hand rather than paying online or swiping a plastic card. It helps many students realize how much they really are spending and keep tabs on what they can afford.

It is important to note that students should never take out a cash advance with their credit cards, because it is a much higher rate charged that begins as soon you receive the money from the ATM. Credit cards are not debit cards, and a credit limit is not what’s left in your “account.” It is important for students to know how much they’ll be charged and know that it’s not a free withdrawal, as this can greatly set them back with the amount of debt they owe.

Credit cards can be very convenient and useful as long as students use them responsibly and don’t spend more than they can afford. Keeping this in mind can help students to spend responsibly, help to keep their debts after college low, and build good credit for their future.