When Sarah* gave $150 as a gift for her friend's wedding, she says she "didn't really give it a lot of thought".
It seemed like a reasonable amount, and she'd already chipped in some money coordinating the hens party and organising bridal events.
But after the wedding, her friend confided that she'd been disappointed by the amount of money she and her new husband had received in their "wishing well", a donation box for guests to give cash to the newlyweds.
"She had expected the wishing well funds would cover the costs of the wedding — or at least come close to it," Sarah says.
"When I walked away from that meeting, I just felt really terrible.
"Once I realised that a friend had given $50 more than me, that's when I really started to spiral and thought, 'Oh God, I've made a huge mistake'."
Sarah shared her experience for ABC RN Life Matters' Too Hard Basket, asking RN listeners if she was living in a "pre-inflation wedding-guest world".
Her query garnered more than 700 social media responses.
"It sounds like your friend has developed a contemporary affliction: Gratitude Deficit Syndrome," wrote one commenter.
"I thought weddings were a celebration, not a money-making enterprise," wrote another.
But although the vast majority of commenters said Sarah's $150 contribution was generous, she can't shake the feeling that she's made a critical faux pas.
"I feel like an absolute cheapskate, and there's nothing I can do about it now," she says.
Why does wedding gift etiquette elicit such strong feelings? And is there a "magic number" to help make the decision easier?
Irish whiskey and hard haggling
Wedding gifts have a rich history, from dowries in ancient Mesopotamia to the earliest gift registries by department stores in the 1920s.
Many would remember glory boxes or hope chests, filled with domestic items and gifted to new brides in the 40s and 50s.
Now, as more couples live together before marriage, cash is the gift du jour — although in many cultures, this is a long-held tradition.
Wedding gifts have long signified more than well-wishes for a bride and groom, says Kiera Lindsey, a research fellow at Griffith University and history advocate at The History Trust of South Australia.
"In the Irish tradition, families were known to sit down at the haggling table for two to three days and with 10 bottles of whiskey before they finally got to the bottom of what they agreed," she says.
If bridal gifts couldn't be agreed on, there could be "an almighty skirmish that could rent a community or inter-country or inter-clan alliance asunder".
Historically, throughout many cultures, Dr Lindsey says weddings have been largely about social mobility, which has been reflected in the gifts bestowed upon a married couple.
"The question is: what does the community give in return for what it receives from the celebration of this new union, hopefully a union that is going to make a contribution back to society?" Dr Lindsey explains.
"So we're really stepping into a long, wide river of tradition when we're [thinking about] what we're going to give as a gift."
And for those with money to burn, wedding presents are an excellent opportunity to show off one's wealth and status.
Take, for example, the lavish 20,000-seat stadium gifted by the ruler of Abu Dhabi to his son; the world's most expensive perfumes, adorned with gold and diamonds, given to Prince William and Kate Middleton by a famous parfumier; and the Greek island given to sports agent Jorge Mendes by footballer Cristiano Ronaldo.
Finding the magic number
For those with more limited means, deciding how much to spend on a wedding gift — particularly if the couple has opted for cash — often comes down to a gut feeling.
In many cultures, that also means taking into account auspicious numbers, familial ties and the opinion of a patriarch or matriarch.
But, according to economist Maria Kozlovskaya from Aston University in England, choosing a wedding gift is also "one of the hundreds and thousands of economic decisions you are making every day, probably without even thinking about it".
When considering how much money to put in an envelope, a wedding guest might assess their relationship to the couple, their financial circumstances or the cost of the wedding — in other words, an internal "exchange rate".
"Every decision we make has a cost, not necessarily a monetary cost, but a cost in terms of what else you could have done with your time, with your money," Dr Kozlovskaya says.
"So how much you give depends on that relative importance of the relationship versus your own personal needs, because both of them are important to you."
She says the figure you land on comes down to finding the balance between the "mental profit" or joy of giving a gift, and the value you'd get from spending the money elsewhere.
Time is money
Part of what made Sarah feel guilty about her gift was the emotional weight attached to it.
"The amount I gave does not properly reflect what this person means to me," she says.
But, according to Dr Kozlovskaya, the time and energy Sarah spent on the wedding are just as meaningful as the money.
"With a wedding gift, you're signalling how important the relationship is to you … It doesn't have to be monetary," she says.
"If you go and help your friend set up the marquee for their wedding, this is signalling [the value of the friendship] because you have just spent your valuable, limited time and effort to help them."
Dr Kozlovskaya is the first to admit that economists are not always the best judges of social etiquette (after all, they have long been against buying Christmas presents), but she hopes they can demystify what is sometimes a stressful decision.
"Giving money is fine. And being practical about it, that's also fine," she says.
And though it may seem mercenary to evaluate relationships in monetary terms, Dr Kozlovskaya says it's an essential part of managing your finances responsibly.
"If you haven't had a particularly good year, in terms of how much you earn and how much you have to spend, it's fine not to give much."
Sarah, however, would rather never analyse her wedding gifts again.
"I probably would just save myself the headache and the trauma and the sleeplessness and just give as much as I absolutely could."
*Not her real name.
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