Editor’s note (2 October). Thousands of Lego fans will descend upon the BRICK fairs in Birmingham and London in October and December, respectively, to meet, play in pits filled with millions of Lego bricks and find vintage treasures. To help them and other Lego obsessives find the best collectable items, a brick-loving story from our archives.

What's hot, what's not

What’s hot: 76023 The Tumbler, 10245 Santa’s Workshop, 41062 Elsa’s Sparkling Ice Castle, 75060 UCS Slave I and 21110 Research Institute.

What’s not: Generic sets and themes that have been released many times, such as cities with mini-figures of pedestrians and police officers. These collections generally lack the “wow factor” that could make them highly prized in the future.

When Tony De Marzio was a boy, he loved acting out stories about King Arthur and his sword Excalibur with his King’s Castle Lego set. Thanks to his grandmother — who saved the box, bricks and instructions — Tony, now 38, has the joy of seeing his 5-year-old son, Anthony, play with the very same fort, horses and soldiers.

“I have great memories of my grandfather watching me build… helping me when I needed it,” said De Marzio, a software project manager in Philadelphia. “The set was difficult to build and I liked the accomplishment when I had finished building and could play with it.”

De Marzio’s decision to get his childhood bricks from his grandmother came after he bought a Lego spaceship as a mobile for Anthony’s nursery, and then an aeroplane. “When I built them I thought: ‘Wow! That brings me back to my childhood.’”

Today, he and Anthony own about 172 sets of Lego. Daughter Natalie, age 2, plays with Duplo bricks, the beginner’s version of the toy.

While the De Marzios appreciate the Danish-made creations for the fun they bring, many sets now have monetary value well in excess of the original purchase price. Some change hands for thousands of dollars.

Increasing numbers of adult fans of Lego, known as AFOLs, are contributing to burgeoning interest. Following 2014's The LEGOMovie, a new film, Beyond the Brick: A LEGO Brickumentary, was released in july, 2015. Meanwhile, fans are flocking to The Art of the Brick worldwide touring exhibition of sculptures made entirely from Lego.

With the current cross-generational craze, it's no wonder a brisk secondary market has emerged in coveted sets and mini-figures.

Who’s collecting and demand

Since setting up a Lego investing website with price guide in 2010, New Jersey-based brothers Jeff and Ed Maciorowski of BrickPicker.com have signed up more than 39,000 members, the founders said. 

“People of all ages collect, but the serious or hard core collectors and resellers that view Lego as a commodity would be about 20 to 50 years of age, with the majority male,” Ed Maciorowski said. He added that female followers are growing in number, partly due to the launch of Friends, a Lego line geared at girls. Enthusiasm is strongest in the US, but also high in the UK, Europe and Australia, and there is beginning to be more interest from Asian markets, he said. 

The appeal

A decade ago, Nathan Sawaya was a corporate lawyer who relaxed after work by building things with his childhood Lego bricks. The hobby so inspired Sawaywa that the 41-year-old has become a full-time artist who has studios in New York and Los Angeles and is building Lego creations that sell for six-figure sums. His touring exhibition The Art of the Brick has attracted millions of visitors in North America, Australia, Taiwan, Singapore, China and Europe.

“Galleries were very sceptical at the beginning. They pictured what they saw in toy stores. It took them seeing the work in person to see it was more than just cars and trucks,” said Sawaya, who collaborated with Lady Gaga to create a headless yellow sculpture for one of her music videos. Simpler works, like Sawaya’s 16-inch high Hugman figures, sell for $300.

“Lego has a timelessness to it. The bricks I had as a child still snap together with the bricks I buy today," he said.

Most coveted

Collectors are beginning to notice the burgeoning interest in Lego toys. For example, the 7884 Batman’s Buggy sold for $9.99 in 2008 recently fetched $138 on eBay, according to Brickpicker. The 10190 Market Street set that retailed at $89.99 in 2007 recently sold for $1,472, while 10179 UCS Millennium Falcon, which retailed for $499.99 in 2007, changed hands for $3,569.

“Most Lego sets appreciate in value,” said BrickPicker’s Ed Maciorowski, “But some take time to hit peak values.” It could take two to three years or longer, he said.

Star Wars kits are among those he expects to increase in value.

Star Wars sets are good choices “with the new movies releasing in late 2015," Maciorowski said. "Superhero sets are solid choices, as are most large and exclusive sets in any theme.”

For best prices, sets should be in mint condition and in sealed boxes. Large sets, and those with short production runs, usually appreciate well, he said. Kits with exclusive and/or multiple mini-figures are good bets, he added. Surprisingly, some sets can be resold for more than the original retail price when “parted out” or broken down for parts.

Where to buy and sell

Tony De Marzio funds new purchases for his family’s collection by trading online on eBay.com and BrickLink.com. In January, BrickPicker also launched brickclassifieds.com. 

New sets are widely available at toy shops and online retailers, but exclusive sets can generally only be purchased through Lego’s own outlets and online store, said Jeff Maciorowski of BrickPicker. Fans who sign up to Lego’s VIP programme are offered early opportunities to buy certain products, he added.

Looking after your collection

As Lego builders since boyhood, the Maciorowski brothers now own about 7,000 sets, stored between their homes and offices.Buy quality shelves and stack sets vertically, like books on a bookshelf,” advised Ed Maciorowski. “Keep in a dark area away from the sun and keep away from moisture, which will easily destroy any Lego box.”

Insurance is a must. “There are collectible insurance companies out there that will insure your Lego collection,” he said.

The bottom line

Profiting from Lego isn't child’s play. Storage space is an issue, as are shipping fees. Even if you trade infrequently there may be local legal requirements around buying and selling. De Marzio, for instance, had to apply to the state of Pennsylvania for a business licence.

BrickPicker’s Ed Maciorowski said: “People can make minimum-wage type of profits or make tens of thousands of dollars a year investing in Lego sets. It depends upon choosing the right Lego sets to invest in, the amount invested, timing and a little luck.

“There are no guarantees and sometimes it can take years to see a profit, but many people do very well if they choose correctly and have a little patience.”

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