“The Joy of Costco” Authors Share Top Shopping Tip — What to Know About 'The Death Star'

“The Joy of Costco: A Treasure Hunt From A to Z” is out now

Some couples share a passion for the movies or even pickleball, but for David and Susan Schwartz, their passion is all things Costco.

“We're like the people who go to baseball stadiums across the country," Susan tells PEOPLE. "Instead, we would go to Costco."

Their love for the membership-only big-box retail store with over 850 locations across the world eventually led the couple to publish The Joy of Costco: A Treasure Hunt From A to Z.

Their new book covers a litany of topics on all things Costco, ranging from the detailed history of the company to store lingo — and even highlights about one store in the Japanese city of Hamamatsu.

“We both came from families that used to go to Costco all the time," David says. "We loved going, and we love the quality, the low price, the fact that you never know what you're going to find in the warehouse.”

Related: Alaskan Man Makes Weekly 14-Hour Boat Trips to Costco to Keep His City Fed amid Pandemic

However, the writing process was a lengthy endeavor that Susan says required the pair, who recently celebrated their 20th wedding anniversary, to travel over 220,000 miles — "three times around the globe" — and visit more than 200 stores.

“It took two years for us to meet Jim Sinegal and Craig Jelinek, the surviving co-founder and the CEO,” Susan recalls. “It took another three years to convince them we weren't going away."

"The company was inherently modest. And after we first met them in 2018, we just kept sending updates to Jim Sinegal, saying, 'This is what we're doing now. This is what's going on now.' And finally, [on] Easter weekend of 2021, we got this email out of the blue from Jim saying, 'Why don't you come for a meeting? We want to make sure the book is accurate,'" she adds.

Self-published under the name “Hot Dog Press” — a nod to the concession treasured by many Costco shoppers — the book is a tribute to the 40-year-old company, and David compares its "quirky" style to a trip to one of the company's warehouse stores.

“Just like when you're in a warehouse, you never know what you're going to find when you turn the corner. In our book, you never know what you're going to find when you turn the page,” says David, who had already written several books when the couple began their journey.

And many of the couple’s favorite finds have found their way back to their 450-square-foot apartment in New York City. “Our apartment now looks like a Costco distribution center," jokes Susan, who previously worked in marketing for Nabisco. "Each place we go, we send home a box that usually weighs [over 22 lbs]."

“You never know what you're going to find because there are only 3,800 items,” David adds. “In order for them to put something new in, they have to take something out. So, there's this constant rotation of items throughout the year.”

Related: Costco Is Selling Gold Bars Now — and They're a Hot Item: 'Gone Within a Few Hours,' CFO Says

And the Costco-fanatics are even sharing one of their top shopping tips to PEOPLE.

“One thing that we discovered is that, if you look, every item has a big price sticker right above it on the shelf,” David says. “If you look in the upper right-hand corner and you see a big asterisk, we call that ‘the death star' because that means that the item is going to either be temporarily or permanently withdrawn from the shelves.”

He notes, “If you see that 'death star' and you want to buy it... buy it, 'cause it might not be there next week.”

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One item that the couple is hoping never receives that sticker is their book, which the couple says will soon be in stores. And though the pair is now focusing on promoting their book, David says they will still make time to stop at Costcos along the way.

For the Schwartzs, the adventure of working together is nothing new — in 2005, they both started their own headhunting firm — yet the ability to travel thousands of miles together has been extremely rewarding.

“This has been a great adventure, a lot of fun and we've learned a lot,” says David.

But if all doesn’t work out, Susan jokes that her husband could get a job at Costco. “David's pretty friendly," Susan quips. "I think he could get a job as a greeter."

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