In three days' time, round £1 coins will stop being legal tender, and you won't be able to spend them in most shops, restaurants and other retail outlets.
But there are still millions of them out there - as much as £420 million worth, according to GoCompare. And across the country, people are checking down the back of the sofa and in children's piggy banks to make sure they find them in time.
See also: Is your new £1 coin worth £3,000?
"Already over a billion of the 1.7 billion have been returned since the new 12-sided bimetallic £1 coin was introduced back in March over forgery concerns, with the Royal Mint estimating one in 30 round pounds was a fake," explains Georgie Frost, head of consumer affairs at GoCompare.
The deadline for spending the round £1 coins is midnight on Sunday. But if you do find some lying around after that, you will be able to take them to a bank.
We look at the different policies of banks and other organisations on exchanging the round pound.
NatWest and The Royal Bank of Scotland
Customers will be able to pay round pounds into their accounts indefinitely, and will also be able to exchange them for the new 12-sided £1. There's no minimum amount.
Lloyds Banking Group says it has no plans to stop accepting old £1 coins from customers: they can be paid into accounts or exchanged, with no minimum amount.
Account holders will be able to pay the old coins in indefinitely, says Barclays.
Santander, too, will accept round pound coins indefinitely, as long as they're being paid into a customer's account. It won't, though, exchange them for the new coins, citing money laundering regulations.
Some stores - such as Tesco, Poundland and Greggs, say they will continue accepting round pounds for a few days after the deadline. Many small independent retailers have said they will do the same.
The Post Office
The Post Office will allow people to deposit their old coins into their accounts with any of the main high street banks.