Using credit cards for purchases has caused ruin to countless individuals and families, especially over the past few years. Easy availability of credit, minimum payments that ensured the card balance would last ten years or more, and seductive advertising combined to force hundreds of thousands of consumers into bankruptcy or into an abyss of endless bills, missed payments, and harassing phone calls.

Those of us who have made it to retirement have usually learned how to use credit cards wisely and we actually benefit from them. Recent moves by credit card companies may soon make that more difficult, but with continued vigilance, we can continue to enjoy the best of both worlds. Here are some of the tips we have learned over the years. One caution: most of these are based on the premise that you pay the balance in full each month.

First, don’t use so many different credit cards. I used to carry cards from all the major department stores, but one day I realized they all accepted major credit cards anyhow, and I didn’t need all those individual cards. I cancelled many, saving a few that offered discounts if you used their store card. I don’t carry those cards, but keep them at home until I plan a trip to that store. Now I use just one card for nearly all my purchases: groceries, drug and department stores, electronics, and most everything else. I have a special card for gasoline that offers better rewards than my everyday card.

Take a survey of your cards, especially if you have accumulated many over the years, and determine which offer you the best deals. Reconsider cards that have an annual fee (although more may be heading that way). Check not only for lowest interest rates, but also for grace period: that is, how long you have to pay your statement after it’s billed before you are charged a penalty or interest. Some grace periods have been reduced to as little as ten days, which is an issue if you occasionally travel for longer than a week at a time. Now that we’re retired, that applies to most of us. Also check their penalty fees for late payments, missed payments, and over-limit fees. These have been increasing recently.

Now that you’re retired, you might decide to cancel some of the cards you have. It’s likely that you will purchase fewer things and have less need for all the cards. It is probably wise to keep one of each of the three major carriers: Visa, Mastercard, and Discover. Many people are loyal users of American Express—that’s fine too. Some merchants accept only one type of card, and if you have cancelled that card, you will have to use another payment method.

Reward points are a big incentive to many credit card holders. For years, I have used my reward points to purchase holiday gift cards, a welcome relief to the budget at that time of year. I have also used points to help with smaller items during home renovation. I purchased light and plumbing fixtures at the local building supply store with gift cards from reward points.

Some people still believe credit cards pave the road to ruin, and these people pay cash for everything. That may be false economy. If you pay cash for goods or services that turn into a problem, you often have little chance to get your money back. Credit card companies serve as an intermediary that will usually refund your purchase and pursue the seller for reimbursement. If you insist on paying cash, carrying a checkbook is bulky. At least use a debit card for your checking account. And if you mean really cash, as in greenbacks only, consider how often it’s necessary to make trips to the bank and how vulnerable you are through accidental loss or even criminals, such as pickpockets, purse-snatchers, or muggers.

Credit cards, when used prudently, are a convenience that can save you time, worry, and money.