The fashion industry has to sell something new every season. The hand fan ruins that arithmetic - it does not change, it is not renewed every year and it lasts for decades. Which is exactly why the object Spain's Queen Letizia has carried since her years as Princess of Asturias is more interesting than any bag from the new collection.

Some of her fans function as documents. One carries an engraved date - 15 July 2007, the day of Infanta Sofía's christening - and she brought it out on a visit to Córdoba and Seville in 2020. Thirteen years on, an object that can still be carried in public because it has no expiry date.

Another is institutional: wood and white fabric bearing the emblem of the Royal Guard, at a ceremony at the air force academy in Murcia this year, matched with Infanta Sofía's fan. There is also one in royal blue with the coat of arms of Juan Carlos I and the Bourbon fleur-de-lis, carried on National Police Day in 2013.

The oldest ones are the plainest

From 2005, the years when she was Princess of Asturias, two survive: one in brown wood and fabric that she used often, and one pared back, where the wooden ribs are almost the entire design, seen on a visit to Ibiza. Twenty-one years later, neither looks like it belongs to another era.

Among them are livelier pieces too - a bright floral one on a visit to San Antonio, Texas in 2018, a Spanish patriotic one in blue with details from the flag, and a completely black minimalist one, both from the military parade for Spain's national day in 2017. And one entirely ordinary, white with natural wood, from Murcia in 2015, the kind that goes with everything.

What the whole collection shows is not taste, but arithmetic. Nine fans across twenty years, most of them carried several times, not one bought because the season demanded it. Here the fan sits in a chest inherited from a grandmother, pulled out once a year for a saint's day or a wedding, and is generally thought of as an object from another time. At forty degrees, it is an object that works better than any smart device - no batteries, no apps, and no need for anybody to upgrade it next year.