Happy Days' time was up when The Fonz jumped over a shark? But how do shows know when they need to end?
Tonight the last ever episode of Wife Swap airs on Channel 4. Next week it is the turn of Melvyn Bragg's The South Bank Show to close the curtain on countless series. When is the right time to pull the plug on long running shows - what are the tell tell signs that a show is beginning to rot?
The phrase "jumping the shark" might not be in common use, but it is the TV industry's favoured term to describe when a particular scene or moment in a series signals the end of what was a great show.
The term originated in the US when producers of the long-running comedy Happy Days attempted to revive its jaded script-lines by having the main character, the Fonz of blessed memory, jump over a shark on a surfboard. The gambit failed and the show ended, but a long-running debate was born.
The Independent's TV critic, James Rampton, believes that there are plenty of examples when shows have lasted too long. He also says that, at present, Gavin and Stacey on BBC 3 "seems to be flogging a dead horse", with characters travelling ever greater distances to meet up.
Doctor Who was transformed by a new production team
There are, he says shows, particularly Ricky Gervais' The Office and Extras, which were short series and left the audience wanting to more.
But it is difficult to know when to stop and great shows are so hard to come by there is often a danger that particularly commercial stations will try and make too much money and over sell the product.
He says that Big Brother is an example of a show on the way out. "I don't think we want more of this laughing at the freaks" he says. But Mr Rampton believes that both Dr Who and Spooks have both retained their freshness.
Stuart Murphy, director programmes at Sky 1 2 and 3 and a former controller of BBC 3, says "I have axed many shows in my time - most recently Brainiac and Gladiators on Sky," he says.
The trick, he explains, is trick is knowing when to do this: if, for example, audience figures fall or a controller wants to take a channel in a different direction. Mr Murphy thinks think Wife Swap is "a perfect example" of a show which is on the way out.
"I think commercial stations are going down the road of bigger but fewer shows," Mr Murphy says. "But, contrary to what James thinks, I think some shows can go on by reinventing themselves and adapt to a changing audience."
He cites Big Brother, which has changed its rules, and other shows which have shuffled their judging panels.
As for perhaps his biggest hit: "I commissioned Gavin and Stacey: it is hard to tell if it has passed its sell by date."
So when does a show go stale and what, if anything, can it do to reinvent itself? Is X Factor losing its shine? Should Strictly Come Dancing now waltz off? We'd like to know what you think, so please tell us, using the form below.
As a species did we just "jump the shark"? Tim, Brighton
BBC2's 'The Restaurant' is a good example of a programme that has peaked. Once, competing couples might have had to cook a shark. Now they can jump one and just have a cocktail in order to win. Peter, London, London, England
Jumping the shark: Radio 4: The Media Show, Off the Page, The Bottom Line, Woman's Hour. All pointless! Radio 3: All of it. Radio 1: All of it. Jamie Bye, Rothley Leicester, England
Father Ted is another classic comedy series that limited its run and preserved its brilliance. Ann , London
Surely Two Pints of Lager and a Packet of Crisps should have been eaten by the shark during its first episode? Chris Went, Cambridge
Jumping the shark. Everyone must say Only Fools and Horses. Then there's Red Dwarf, Friends, Eggheads. They managed to bring Countdown back from the dead, however. Helen , Cromer, UK
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