I have more than a half dozen credit cards in my wallet. A new app on my iPhone, Glyph, tells me which of these credit cards to reach for to get the most rewards when I'm buying groceries, getting gas, dining at restaurants or shopping at Macy's or CVS.

At least two of the credit cards I have, Discover and Chase, and for the Chase card more specifically I have the Chase Freedom®, change their extra reward categories frequently. I have to say I'm good about signing up for those promotions and remembering whether this month it's gas and groceries or restaurants or department stores. These cards also have quarterly spend caps for the quarterly categories.

Downloading the Glyph app to my iPhone was easy enough, even for someone who is as technology-inept as I am at times. But when I went to use Glyph at the restaurant in D.C. where we had lunch on Saturday, I had forgotten my password so I couldn't log on. I had written my password down in my planner as I do all my passwords, but my planner was back home in Pennsylvania. It wouldn't do me any good. By the time I asked Glyph for password help, my husband had already paid the bill with our Discover card.

Do your cards make the list?

Once you download Glyph to your smart phone, it asks you to check which credit cards are in your wallet. Makes sense. How else can it tell you which is the best card to use when you're standing at the register or making a purchase online?

Glyph says it supports more than 250 business and consumer credit cards and is adding more daily. But when I signed up in mid-November, I couldn't find the exact two I use most often. They may have been there, just under another name, but I couldn't tell.

In an email exchange with Glyph CEO Mike Vichich, he says, "Glyph includes the top 18 credit issuers in the USA and over 260 credit cards, which covers greater than 90% of all transactions. Having said that, we are adding new cards every day. We have a feature in the app whereby users can inform us if a card is missing; we address those missing cards in prioritized fashion."

Consumer advocate and credit card expert John Ulzheimer, president of Consumer Education at SmartCredit.com, had a similar experience. "I have a credit union issued Platinum Visa that is 'missing' from their inventory," he says.

Answers could be the same

I found that Glyph was helpful the first time I shopped for groceries or bought gas, but since I shop at pretty much the same stores after a while it's going to tell you the same thing. And so it's just taking more valuable time to check Glyph before I pay. Yes, your credit cards and merchants may be offering special promotions, but, as I said, I pay close attention to them. If you're not dilgent about checking reward programs, having Glyph on your smartphone may be more beneficial.

The Wallaby card is similar idea. Like Glyph, it automatically picks the best card for you to use every time you need to swipe. The Wallaby card is free for the first six months and $50 a year after that. I don't think it's worth spending $50 for it. Wallaby's website reads "we know you'll make up for that in new cash back or points." I'd rather just get the points or rewards myself.

The Glyph app is free which makes it a far better choice - though it looks like you'll have to put up with ads in exchange. In the future, it may offer premium features for which you must pay.

Will you spread your rewards too thin?

Although I have a selection of credit cards, I generally use either Discover or Chase Freedom®. My thinking is it's better to use the same cards repeatedly so that I can rack up enough points to where I can cash them in for rewards. If I spread out my purchases among too many cards, I have too few points on any of them to be of value.

Consumer advocate and credit card expert Beverly Harzog of Atlanta has another concern. If the app is used to determine which card to use to maximize rewards, that's fine, she says, "But I worry it might encourage excess spending because of the rewards involved."

Getting 5 percent cash back is a nice bonus, but only if it's something you really need to buy anyway. Five percent of a $250 item ($12.50) you didn't need or will regret buying later isn't going to get you very far and you're still out $237.50.

Will using Glyph help you make the most of your rewards and cash back credit cards? It might be nice to have one less thing to keep track of in the world and let the app make the best call. But if you're like me, happy to monitor my credit card programs, then Glyph probably won't tell you anything you don't already know.

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