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Rewards earned from spending with a credit card can help you obtain cash back, airfare, hotel stays, gift cards and more. So why let them go to waste?

According to a recent Bankrate Credit Cards survey, 46 percent of U.S. adults participating in airline and hotel rewards programs have, at some point, let their points or miles expire. Among those who collect credit card rewards, 29 percent allowed their rewards to expire intentionally.

Other surveys have detailed similar findings in the last few years. A 2017 study by Bond Brand Loyalty, ran in collaboration with Visa, found that one-fifth of those participating in a loyalty program have never redeemed their points.

“A lot of people are sitting on airline, hotel and credit card rewards that are worth a significant amount of money,” says Bankrate credit card analyst Ted Rossman. “That’s why it’s so important to take advantage of them before they expire.”

Expired points and miles: Millennials are losing the most

Of all generations, millennials are most likely to lose their rewards from expiration.

In fact, 57 percent of millennials have lost hotel points compared to 41 percent of older adults and 50 percent have forfeited airline miles in contrast to 46 percent of older adults.

Why rewards are going to the wayside

Perhaps the number of individuals not participating in rewards redemption can be traced back to an overall lack of awareness concerning the worth of their loyalty program’s rewards.

Fifty-three percent of U.S. adults admit they have no idea how much 10,000 points or miles are worth (the answer being roughly $100 to $199 range or 1 to 2 cents apiece). According to the survey, only 18 percent of U.S. adults are aware of this.

What causes point and mile expiration

One of the most common reasons for point and mile expiration is an inactive account, and the length/definition of inactivity varies based on the loyalty program.

Delta, for example, doesn’t have an expiration policy — meaning your miles earned with the airline will be available to you so long as your account is open. On the other hand, Southwest Airlines will expire any miles you’ve earned after 24 months of no earning activity.

Ways to prevent wasted rewards

First and foremost, you’ll benefit from brushing up on the points and miles expiration policy for each of the loyalty programs you’re apart of.

If you find yourself cutting it close with a certain program’s expiration policy, Rossman suggests combating this by demonstrating new account activity.

“This can involve a small purchase or redeeming a minimal number of points or miles,” says Rossman.

For example, you could redeem for a hotel stay, flight or even merchandise within your loyalty program’s shopping portal.

One of the easier ways to indicate account activity is by donating your points or miles to charity, if possible. American Airlines offers three options for doing so  — you can donate your miles to organizations focused on improving society, health or supporting past and present military members and their families.

Another simple way of maintaining account activity is transferring points or miles earned on your credit card to your loyalty program. Not every card is going to offer this perk, but many travel rewards cards do.

For example, Chase cards that offer Chase Ultimate Rewards, such as the Chase Sapphire Preferred® Card, allow you to transfer your points earned to one of their 13 hotel and airline partners. Better yet, your points transfer at a 1:1 value, meaning they won’t decrease in worth.

The bottom line

You’ve worked hard for your points and miles (whether you know it or not), so you might as well keep them in your possession. You can find our list of best credit cards for airline miles here.

By familiarizing yourself with your loyalty program’s rewards expiration policy and keeping your account active with small purchases, point transfers or donations, you can make sure your points and miles stay right where they belong.