They may have been full of good intentions, but it turned out that rewards card holders did not use their accumulated rewards points the way they said they would do so this summer, according to the Capital One Rewards Barometer.

Capital One's Rewards Barometer is a quarterly survey of American consumers that tries to get a pulse on how they collect and redeem credit card rewards. This past May, Capital One asked how many people would be using their rewards for travel during the summer vacation season. In that survey, 33 percent of respondents said they'd be putting their rewards points to use to help pay for their summer vacation. In this new survey, only 21 percent actually followed through and used those rewards.  

Part of the reason why not as many people used their rewards as anticipated isn't because they simply forgot to use them, it's because they couldn't necessarily redeem them. The top reason card holders didn't use their rewards is because they didn't have enough points to do so. 43 percent of survey respondents had this issue.

Other main reasons people couldn't redeem their card rewards were due to blackout dates and lack of availability.

"Card holders should understand that sometimes it can be difficult to use the rewards they've earned with some programs," said Amy Lenander, vice president of rewards programs at Capital One, in a statement.

It's a good idea to learn the guidelines about redeeming the points and miles associated with a rewards card before users try to cash them in. While these programs promote "free travel," the programs may ask participants to pay for airline taxes, fuel surcharges and even booking fees when they try to redeem rewards. The barometer found that this was true for 37 percent of respondents, who found they had to pay fees when they tried to book rewards travel this summer.

Also frustrating can be learning that you have to pay fees in order to redeem rewards for travel. Capital One's survey found this was a fairly common misunderstanding, with over one-third of survey respondents admitting that they don't know whether or not they're going to be charged extra fees if they're trying to redeem their rewards for travel.

"Take the time to understand your rewards programs. Before you plan your next trip, find out if you need to pay anything out-of-pocket to redeem rewards, and if you can cover extra fees, like checked baggage fees, using your credit card rewards, said Lenander.

Now that the summer travel season is nearly over, card holders who are part of rewards programs that have flexible terms and different rewards categories to choose from might change their priorities from vacations to back-to-school shopping. The barometer found that 60 percent of surveyed parents with rewards cards planned on spending anywhere from over $100 to $500 per child to prepare for the new school year.

Some card holders have even decided to think past summer travel and ahead to using their rewards for holiday purchases. According to the survey, 32 percent of rewards card are thinking ahead to the holiday season and putting their rewards toward saving money on gifts for family and friends. A good 13 percent have already planned on doing so, with the majority of respondents opting for gift cards over merchandise.

This quarter's Rewards Barometer also confirmed that cash rewards remain the biggest draw for consumers who like to earn and redeem credit card rewards. While cash is redeemed most often, with 42 percent of respondents redeeming points for cash, domestic airline tickets and gift cards are other top rewards options.

The Rewards Barometer, conducted by BIGinsight, surveyed 1,045 adults 18 and up who have a rewards credit card. The survey had a margin error of /- 3.1 percent.