My key chain and my wallet are bursting with cards for frequent flier programs and retailers' loyalty clubs.

I carry cards for 20 companies in my purse every day I leave my house. (That's not an exaggeration: I counted.)

Truth be told, I don't really mind, because I think these programs pay off.

Recently we booked a flight using miles earned through one of our credit cards, and I redeemed points from another program to get a Starbucks gift card.

My general philosophy is that almost all of these programs are free to join, so I might as well join so I can get a bonus for my normal spending.

But Robert Passikoff, president of Brand Keys Inc. in New York, said some people don't get as much from these programs simply because of the kind of shoppers they are.

There are folks like me who diligently collect and track their points until they can cash them in.

Others like instant gratification and cash in points as they earn them, getting smaller prizes.

But the majority of users are in the middle, accumulating points and not tracking them closely. That can lead to the unintended loss of points when they expire.

Consumers as a whole have started to resist these clubs, because it seems that nearly every retailer has one, Passikoff said.

If you belong to one, the best advice is simple: Keep track of how many points you have, and use them before you lose them.

If you're not using the points, maybe you don't need the account.

For me, that means checking my accounts on a regular basis, every month or two. Some loyalty clubs even do the work and send me monthly statements.

Don't dally: Redeem the points

Check out the lists of items that you can get for your points.

You shouldn't necessarily wait until you have enough for a trip to Hawaii. A $25 Home Depot gift card can be useful, and getting it is much better than losing points because you weren't paying attention.

You could even cash your points in for several small gift cards, then give them away.

If you have miles or points idly sitting around, here's my final plea: Do something.

If nothing else, lots of programs, including Lowes Foods Greenpoints and American Airlines' customer program, will let you donate points to charities, friends or family. What a nice gift.

This month, we reported that the state had collected more than $12,000 in fines from six Wake County stores that were found to have too many discrepancies between their advertised prices and the prices that rang up at the register.

This takes me back to advice I often share: Check your receipt. Do it before you leave the store. And do it every time you buy something.

Scanner errors happen more frequently than you would think. That's partially because stores carry more items than they used to. The average grocery store stocks 45,000 items.

In addition, stores put thousands of new items on sale each week. It's no wonder that occasionally there are mistakes.

You can protect yourself by checking your receipts for errors and knowing the stores' policies on scanner errors.

At the very least, any store should be willing to refund you the difference between the advertised price and the price you paid. (If a store isn't willing, return the item on the spot, and go shop somewhere else.)

Many chains, including Food Lion, Lowes Foods, Harris Teeter and Kroger, have "scan right" guarantees that offer the item for free if there's an error.

You can't beat free.

To me, it's worth a few minutes in line at the customer service desk, and speaking up also keeps retailers aware of mistakes in their systems.

For those who are wondering, Savvy Consumer columnist Vicki Lee Parker will return in June -- savvy as ever.