It's no secret that weddings aren't cheap.
The average cost of an American wedding was $35,329 in 2016, according to the most recent figures from the Knot. But as costs go up, the number of guests at weddings is going down, according to the Knot's annual wedding trends report released Tuesday.
Young people getting married are more interested -- and more invested, to the tune of tens of thousands of dollars -- in creating a unique event for their wedding, says the Knot's Editor in Chief Kristen Maxwell Cooper.
"It is very expensive, but people are still spending on this part of their lives," says Maxwell Cooper. "But the guest count has dropped. They want to create a one-of-a-kind experience. Something that stands out as an amazing event on social -- that's where they want to put their money."
And chances are, young people will continue to put their money toward major YOLO extravaganzas.
"I don't see this changing," says Maxwell Cooper. "Maybe if we hit a recession, spending on weddings will dip. But I'm doubtful young people will flip the switch and suddenly decide to save this money for a down payment on a home."
That down payment? That's what the cash registry is for.
Here are some other wedding trends from the Knot report.
Fewer favors, more "wow"
The little odds and ends that the bride and groom tend to give as take-home treats, are disappearing in favor of a more experiential wow factor.
"Millennials, and I mean this in the best way, are a vain bunch," says Maxwell Cooper. "They put their whole lives on social and a wedding is no different. They will continue to put their money toward their wedding as an event for their guests to experience and put on social."
An unexpected band, additional entertainment, a venue that drives people to Insta, that is what couples are going for, according to the report.
"It is no longer 'Do you want chicken or steak?'" says Maxwell Cooper. "Maybe it is heavy-passed hors d'oeuvres, but every item tells a story of the couple."
When most wedding guests have come to appreciate a good dinner out, the bride and groom are finding there is an interest in providing foodie-caliber food.
Perhaps it is a "his" and "hers" menu option, open fire cooking or chefs plating food in front of the guests -- something that leaves guests with an experience in addition to tasty food.
It's cool to ask for money
In some regions of the country the only truly acceptable wedding gift has always been money. But in other areas, it has been seen as uncouth and crass to have a registry for money.
Most couples will still have a traditional registry, says Maxwell Cooper, but many will also have a cash registry.
She points out that as people are getting married older, with more established careers and even a home together already, many couples don't need the tea-towels and silverware that populate traditional registries.
This may be for traditional newly-wed expenses like a honeymoon or a new home, or more modern ones like paying for IVF or adoption or spending a year abroad.
"Create a story around what you're asking for, maybe the money is going to go toward travel, or a bathroom renovation or a new puppy," says Maxwell Cooper.
"They really do value experiences," she says. "They already have everything they need."