Every time British currency is withdrawn to make way for its replacement, there's advertising urging people to trade in their old coins/notes for new with a cut off date when old currency will no longer be honoured by retailers and then banks .. I bet there's some mad stories involving 'under the bed' cash hoarders being turned away past the deadline.
No need to panic, even then, of course - banks (if necessary, the Bank of England, as a last resort!) will still accept out-of-date money. It's not as if the currency itself is changing, after all.
Taking this thread further away from its intended journey, I'm reminded of the scare stories about the Royal Mint that were on TV a month or 2 ago. As you probably mostly know, the Mint produce any number of special coins, above and beyond what we see in our change - £5 and £20 coins, and even a £100 coin quite recently. I myself bought a couple of the recent Winston Churchill £20 coins - made from silver, and available from the Mint at face value.
Anyhow, some customers of the Royal Mint were on
Watchdog or some similar programme, moaning that they'd bought some of these commemorative coins as an investment, possibly paying a premium in some cases, but when they'd come to sell them, collectors wouldn't even give them face value. "What a con!" seemed to be the gist of it. Well, my answers to that whinge are several: first, buying anything as an investment is very unpredictable, and hoping to make a profit on a fairly modern coin sounds
extremely risky. Second, the Royal Mint will not, in any case, make the claim that all of their coins will rapidly increase in value, so the cries of "con" are invalid. Third, if you
really want shot of your unwanted "collectible" coins, then most banks will be only too happy to oblige - at face value, of course. The reason that some collectors will offer less is that
they have then got to go to the trouble of going to the bank to do just the same.
For me, I have a few coins which I would deem collectible, but I wouldn't confuse that word with "inflation-busting". Generally, I buy something because I like it, and am happy to pay the price asked, not for profit. Take a look at the Royal Mint's site, and decide whether you really need the latest Beatrix Potter-themed 50p in pure gold for £675, or whether you'd prefer something cheaper:
http://www.royalmint.com/shop/Beatrix_Potter_2016_UK_50p_Gold_Proof_Coin
Me, I'm slightly more tempted by the new £50 coin:
http://www.royalmint.com/shop/Britannia_2015_UK_50_pound_Fine_Silver_Coin
Sorry for letting my musings carry me off topic once again.