Round pound coins will start being phased out at the end of March and will cease to be legal tender this October.
It means it's time to start emptying out those piggybanks and checking down the back of the sofa to make sure you don't get stuck with cash you can't use.
But before you spend them, it's worth making sure that you shouldn't be selling them instead, with some ordinary one-pound coins in circulation worth up to £30 to collectors.
Is your £2 coin worth more than £300?
According to the Change Checker website, the rarest pound coin in circulation is the Edinburgh £1, one of four produced to depict the UK's capital cities.
Fewer than a million of these coins were minted, and if you're lucky enough to find one in perfect condition, it could be worth as much as £30. It was Change Checker's most-requested coin last year.
The 2011 Cardiff coin and 2010 London £1 coins, part of the same series, can be worth almost as much.
And other valuable £1 coins include the 2008 Royal Arms £1, the 2014 Thistle £1, the 2013 Daffodil £1, the 2013 Rose £1 and the 2014 Flax coin.
The new 12-sided pound coin is being introduced to make life harder for counterfeiters - currently, an astonishing one in 30 pound coins is fake.
Described by the Royal Mint as 'the most secure coin in the world', it incorporates a hologram that changes from a '£' symbol to the number '1' when seen at a different angle.
New quid on the block: 12-sided coin to replace round pound on March 28
And with the disappearance from circulation of the current round coin, it's worth looking out for the collector's pieces of the future - some of which may not be particularly in demand now.
"The coins which have the greatest value are ones which were also issued by the Royal Mint in collectable packages of four and, therefore, are in the best condition," Rob Brannagan, of coin trading firm Scotmint, tells the Daily Record.
"People should also keep any shiny new ones which have been recently issued as they could be of value in years to come after they have passed out of circulation."