You may pop open a bottle of champagne to celebrate something good, and perhaps you will keep the painted metal cap which secured the cork as a wee souvenir of that moment.
But for a small but growing number of hobbyists, champagne cap collecting is more than just about fond memories. For them, it's a passion and an art form – and, for a few, a livelihood.
"There are some caps which are worth 10 times the price of the bottle," says Pascal Dorme, a trader who organises a "worldwide" cap fair in the wine-growing village of Mesnil-sur-Oger, east of Paris.
"It's all to do with rarity, supply and demand, and prices can range from 50 centimes (RM2.25) to 1,000 euros (RM4,495) apiece."
The sparkling wine of France's Champagne region was invented around two centuries ago, but in the early decades, lovers of bubbly would often be cruelly disappointed.
If there was just the tinest gap between the cork and the neck of the bottle, the precious carbon dioxide gas in the wine would escape... and fizzless "fizz" would be the sad result.
Scroll forward to July 1844, and a wine merchant by the name of Adolphe Jacquesson came up with an elegant (and patented) solution.
He thought of a small metal disc, slightly wider than your thumb, that would be placed on the top of the cork and tightly secured with a "muzzle" made of thin wire.
That way, all-round pressure would be exerted on the cork, providing a perfect seal – a technique that is still used today.
By the end of the 19th century, producers learned that the cap could be incorporated into the lucrative mythology of champagne.
It could be used for a tiny piece of artwork, adding a dollop of luxury and sensuality to the high-class beverage.
Some of the most coveted caps are hand-painted or silkscreen-painted, silver-plated or even solid gold.
But there are also highly valuable caps made from the rough-and-ready metal of the early industrial era.
The pictures on the little discs, too, are eclectic.
They can range from the coat-of-arms of the wine-growing family and art-nouveau pictures, to a commemoration of a big year in history, such as the start of World War I or the 1999 solar eclipse in France, as well as portraits of family members or even pets.
Rarity, as well as the emblem, makes a huge difference to collectors.
For the best-selling brands of champagne, hundreds of thousands of caps may be manufactured, and their price is unsurprisingly low.
But there are also tiny brands that sell to a connoisseur market. Their caps fetch hefty prices, "and can rocket if a decision is made to halve a year's production, from 1,000 bottles to 500," says Dorme.
With an eye on the collectors' market, some producers create limited editions of caps, or change the artwork every year.
A one-day fair – held every two years since 2007 – recently drew 100 stands, with traders showing off their wares in handmade, velvet-lined cases.
They were mobbed by a crowd of 5,000 collectors, called "placomusophiles" in French, a composite word combining the terms for cap and wire.
The hobbyists' bible is "le Lambert" which gives the market value of 30,000 out of the 45,000 champagne caps believed to have existed.
The rarest caps can change hands for up to 10,000 euros apiece. Only three "Pol Roger 1923" caps were made – a status that puts it into the category of a rare stamp or coin.
Stephane Primault began trading in caps at a market in Reims, the "capital" of Champagne country, when the hobby took off in the 1980s.
"My father worked in the vineyards, and at the time it was easy to pick up these little discs which no-one wanted," Primault tells AFP.
"I started off by swapping caps one for one to build up a collection, and now it's my livelihood."
Primault boasts an inventory of more than 30,000 caps, 3,000 of which are pre-1960 – a threshold date between "new" and "old" caps.
He says he has a list of loyal customers, and while other traders buy and sell through the Internet, prefers to do business the old-fashioned way, by telephone and paper. – AFP, March 14, 2016.