Americans are notoriously bad at taking vacation. In fact, Project: Time Off estimates that 54% of Americans left 662 million vacation days unused in 2016. Of these days, 203 billion were forfeited, meaning they didn’t roll over to the next year. These lost days added up to $66.4 billion in forfeited benefits across the workforce, or $604 per worker.

There’s a host of reasons why people don’t take their time off, whether it’s family obligations, work stress or lack of funds. That said, one common obstacle is simply lack of preparation. Which is why Jan. 30 has been named National Plan for Vacation Day. (We should note that Project: Time Off was started by the U.S. Travel Association, a travel industry group, so not surprisingly it wants to urge people to get on planes and stay in hotels.)

On Tuesday, Project:Time Off is urging Americans to sit down with a calendar, pick a vacation date and start putting together an itinerary for a trip. It may sound tedious, but the benefits of planning ahead are easy to see. In total, 52% of people who planned their trips actually took all of their vacation time, compared with 40% of non-planners, according to Project: Time Off.

Planners are also better at setting aside enough time for some real rest and relaxation. More than 75% of planners were more likely to take a full week of vacation at a time, versus non-planners who are more likely to take zero to three days. Another obstacle is taking quality time off. In a survey by job site Glassdoor, 29% of employees said they stayed in communication with coworkers while on vacation, and 25% report being in contact with their boss about work matters. So not exactly in full rest and relaxation mode.

If you’re one of the millions of workers leaving vacation days on the table, you might want to reconsider your strategy. Taking days off has been shown to improve work performance, improve personal relationships and promote better health.

So take some time today to plan some time off. As you move forward, use these tips to find the best deal.

Set a price alert

You don’t have to commit to a vacation today, but you can start researching flights, prices, and destinations. One way to get a good gauge on airfare prices is to set a price alert on your favorite booking site. Whether you use Kayak, Hopper, Momando or Fare Compare, setting a price alert means you’ll be notified when airfare to your preferred destination drops. This way you can pounce on low airfare the moment it becomes available.

Know when to book

Airfare fluctuates constantly, but there are some overall strategies to get the best price. For example, Hopper estimates that shoppers need to buy airfare about six weeks in advance for busy Easter travel. This means buying your plane ticket around Feb. 18 if you want to travel around April 1.

For Memorial Day (May 28), travelers should book travel by May 7. For the Fourth of July, they should book by June 13, and vacationers should buy airfare by Aug. 13 for Labor day (Sept. 3) travel.

Knowing which month to book can also save you money. In general, airfare starts to increase dramatically in May, and stays relatively high throughout the summer. If you’re looking for a deal, consider flying in shoulder season, either April or September, to find more affordable flight options.

Take advantage of points and miles

Planning ahead also gives you the opportunity to take full advantage of credit card travel perks. Every card is different, but customers are usually required to spend a certain amount in the first three or four months in order to earn the sign-up bonus. For instance, the Chase Sapphire Preferred card rewards users with 50,000 points after they spend $4,000 in the first three months. Those 50,000 are worth about $625 in airfare or hotels when booked through Chase Rewards.

Signing up for a credit card now means that you’ll probably be able to use your sign-up bonus points in time to book summer travel. If you have a good credit score, and like to travel, here are some credit card options that can help you to earn points.

Brittany is a reporter at Yahoo Finance. Follow her on Twitter.

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