Most of us expect to sell our home for more than we paid for it - particularly when we've invested in improvements.
While house prices have fallen over the last three months because of fears over Brexit, there's been a general upward trend for decades. And renovating, extending and redecorating usually bump that profit up.
However, this isn't always true of celebrity homes, with research from US estate agent Redfin finding that they tend to stay on the market for a month longer than other homes, and usually sell for less than the original asking price.
The reason seems to be that celebs tend to over-develop their homes - or develop them in a particularly personal way.
"Celebrities will sometimes add amenities to a home, which might not be a selling point for future homebuyers," says Redfin's Alec Traub.
"For example, a celeb might install a basketball court in the basement of a home, where another person might want to use that space for something else. Those homebuyers may be less inclined to want to pay the initial asking price."
We look at a few who made a property loss.
Posh and Becks
This summer, we took a peek at the six-bedroom house in Bargemon, Cote d'Azur, that the Beckhams have been trying to sell.
The couple bought the house for £1.5 million in 2003, and then spent £5 million on renovations, having one living room painted purple and the dining room kitted out in medieval style.
However, the house still hasn't sold - and even if it does make the £2.4 million asking price, they Beckhams will make a loss of more than £4 million.
The former Take That star paid a whacking £8 million for his seven-bedroom, eight-bathroom Wiltshire manor house in 2008. However, just 18 months later, it was on the market again, at a cut-price £7.5 million.
Earlier this year, he tried again - putting it on the market for a bargain-basement £5.5 million.
Sarah Jessica Parker and Matthew Broderick
The acting couple bought a New York townhouse for $19 million in 2011 - and spent a fortune doing it up. However, when they tried to sell it a year later, they failed to reach the $20 million price.
It took them until last year to shift the property, for just $18.25 million, representing a significant loss.
The Oscar-winning actress bought her Hollywood penthouse for $2.75 million in 2007. However, when she came to sell the one-bedroom, loft-style penthouse earlier this year, she reportedly netted just $1.75 million.
Perhaps the most extreme example of a celebrity making a property loss is acress Kim Basinger. In 1989, the actress bought not just a house, but a whole town.
She paid $20 million for Braselton, in Georgia, but fell into financial difficulty - and sold it five years later for just $1 million.