Turn that stockpile of miles or points into a trip

Americans are sitting on a massive stockpile of unused travel rewards. Cardholders earned more than $34 billion in credit-card points alone last year, according to reports from American Express, JPMorgan Chase and Capital One.

The longer these points and miles go unused, the more value they lose as many airlines make it harder to find cheap award fares. “That’s basically money that’s not earning interest," says Bart Welch, co-founder and chief executive of rewards-travel website PointsYeah.com.

Instead of letting your rewards sit there, now is the time to put them to use.

1. Evaluate your stockpile

Before booking, do a quick inventory. Check all the rewards you have with credit-card companies, airlines and hotels. See which account has the largest stash, and double-check if any of your points or miles might expire.

Germán Ceballos, head of marketing at AwardFares, a site that monitors reward-flight availability, recommends doing this periodically. Checking every six months should be plenty.

2. Set travel goals

Many people collect—and hold—so many points and miles because they dream of bucket-list trips. And it is possible to book that African safari or Tahitian getaway entirely on points.

But that usually isn’t practical. Unless you’re a road warrior or credit-card guru, it will take ages to earn enough points for such a trip, and the points you’ve earned could lose value while you wait.

Frequent-flier pros recommend setting a variety of travel aspirations. Some can be long-term dream vacations, others more simple, like a weekend getaway or a family visit. Then think of your credit-card rewards as you would your actual cash reserved for travel: It’s often fine to spend some now and some later.

3. Research flight prices

If you don’t have a destination in mind, let flight prices guide you. Check a site like Google Flights or Kayak to find affordable locations.

With most airlines, rewards pricing is often tied to airfares, though some airlines maintain static award charts.

4. Explore rewards deals

Flight-reward search tools such as Point.me, Roame, PointsYeah.com or AwardFares show which award trips are cheapest for a given itinerary. If you’re using credit-card points, it’s often cheaper to transfer the points to an airline’s frequent-flier program and book through the airline, rather than your card company’s own travel portal.

If you do go through your card company, stick to the rule of thumb of aiming for 1.5 to 2 cents a mile or point spent. Here’s the math: Spending 25,000 points for a flight that would cost $500 in cash equates to a point value of 2 cents, while spending 50,000 points would decrease the value to 1 cent.

Be sure to factor in any taxes and fees you’ll need to pay in cash. And remember, if you transfer points to an airline, you can’t transfer them back.

5. Don’t forget the hotel

Travelers often think about flights when redeeming rewards, but hotels can be a good target for those points. Follow the same steps outlined above, but for lodging.

At the very least, be sure to research room rates in your destination before snagging a flight. Hotel rooms in many popular destinations cost a lot more these days, which could outweigh the savings derived from using points for airfare. Thinking through these details might seem like extra work, but it could mean a cheaper trip later.

Sign up for the WSJ Travel newsletter for more tips and insights from the Journal’s travel team.

Write to Jacob Passy at jacob.passy@wsj.com