We talk a lot about what you can do with credit cards and how you can make their terms, perks, and special offers work for you. Today let’s look at the other side of credit card usage — things you should never do (or at least things most of us should never do). Take these tips as cautionary pointers to help you maintain your security and avoid potential financial problems.

Here are five things you should not do with credit cards:

1. Don’t keep all of your credit cards on you at the same time.

If you always carry all of your credit cards with you in your wallet, what happens if that wallet is lost or stolen and you need access to funds? You might be out of luck — at least in the short term. Yes, you can get them replaced, but sometimes you just can’t wait. Always keep at least one credit card with an available balance separate from the rest so if you run into trouble you’ll have a backup plan.

2. Never spend more than you make.

Unless you’re independently wealthy so you don’t have to worry about “making money” anymore, use your paycheque as a guide when it comes to credit card spending. While it’s okay for some people to finance things over time once in a while (if they’re disciplined enough to pay the balance down quickly to avoid huge interest payments for example), try to make it a general rule that if you can’t pay it off that same month, you won’t buy it. That’s probably the best thing you can do as a cardholder to help yourself avoid going into credit card debt.

3. Never loan your credit card to someone else.

There really isn’t a good enough reason to put your credit cards at risk by giving them to someone else. If someone’s authorised on your account, get them their own card. Otherwise you let someone else be responsible for your financial future and the security of your credit card information.

4. Don’t make purchases solely to earn more rewards points.

It doesn’t matter how close you are to earning the rewards points you need for that free flight you want to book. If you make a purchase just to earn those points, that’s irresponsible. Only use your rewards cards to make the purchases you would make anyway. The purpose is to reward you for your existing purchasing behaviour and customer loyalty. Rewards cards and frequent flyer cards (like the Earth Platinum credit card) should not be used as an excuse to overspend or go in debt. That defeats the value of any rewards earned.

5. Never (never ever ever) make only the minimum payments.

There really is no excuse for consumers to make only the minimum payments on their credit cards. If that’s all you can afford to pay, then you’re spending outside of your means. And you’re going to pay ridiculously more than you should for even the most routine purchases because of the interest you’ll pay over time. Remember — minimum payments are in the interest of the credit card company, not the consumer.

Do any other big credit card “no-nos” come to mind? Share them in a comment below.