It is the eternal argument - which was better, the book or the film?
Should you watch Lord of the Rings first, or read the books? What about Game of Thrones - will reading the books now just ruin the suspense, or will it add to the back story?
Should they even bother making the last Hunger Games into a film?
Since the first film reel flickered into life, it has been an issue to contend with. And in recent years, every second book seems to have been thrown into the widening vortex of film or television adaptation.
You cannot go to the movies without running the risk of seeing one of your favourite characters ruined forever, or watching every plotline you love being torn apart for the sake of a speedier narrative.
If you think it is tough being in the audience, imagine the pressure brought to bear on the screenwriter or director trying to bring a much-loved book to life - or on the author, forced to relinquish control on a piece of their work.
So what is the recipe for a successful film adaptation? And how do some directors get it so wrong?
Oscar-winning screenwriter Philippa Boyens admits she could not bear to read Lord of the Rings ever again.
Her once-favourite book, which she had already read eight times before agreeing to co-write the screenplays with Sir Peter Jackson and Fran Walsh, will never be the same.
She has dissected the actions of every dwarf, analysed each fight scene, gleaned minute details of every tree and rock and landscape.
"When you adapt it you kind of lose it forever, because you have a different knowledge of it now," Boyens says.
She is currently in the middle of post-production for the third instalment of the $500 million The Hobbit trilogy, her most recent work.
The screenwriter says it is "hugely daunting" approaching a novel, especially one that has given rise to to as many passionate fans as the J R R Tolkien series.
While it was important to keep in mind how beloved the books were, it would be an error to let them dictate your every move, Boyens says.
"There's two ways of approaching it. One is to be fearful of putting a foot wrong, in which case you are dooming yourself to fail anyway. Fran [Walsh] always says by its very nature, taking a book and putting it on screen, you are changing it.
"Your adaptation is just your version of a piece of literature, a piece of work that you love as much as anyone else. You cannot take on the responsibility of making a definitive version of The Lord of the Rings, because you would fail."
The other way is to look for what drives the storytelling, and find ways of getting it across visually.
With The Hobbit, this included creating an entire character that does not appear in the book. Tauriel, the fighting elf played by Canadian actor Evangeline Lilly, was designed to bring a "female energy" that was missing from the story, Boyens says.
"When Tolkien wrote the plot he was writing a children's story, he was not conceiving it as a film. He was writing against a visual landscape of his own creation . . . the way I like to think of it is that he did not write her into The Hobbit because he did not need to tell the story in that way - but we did.
"The female energy is great, and she's become one of the most popular characters in the film so I feel like we made the right choice there. It allowed younger women a way into the story, and it also leavened it because you can feel the blokiness of 13 dwarfs after a while."
While it is impossible to ask Tolkien what he thought, other authors have been blunt when it comes to critiquing film versions of their work.
In 2009, writer Elizabeth Knox told the Dominion Post she lay in bed and cried for days after watching director Niki Caro's adaptation of her novel The Vintner's Luck. Knox said she was shocked and upset by how much it departed from her story.
"She took out what the book was actually about, and I was deeply surprised and deeply puzzled by it, because I do not know why she did it."
Reviewers echoed Knox's sentiments, with the Hollywood Reporter calling the film "an overblown work of amazing silliness".
Caro declined to be interviewed for this article.
Author Roald Dahl famously said the film version of Charlie and the Chocolate Factory was "crummy" and vowed never to allow its sequel.
Stephen King hated The Shining, the 1980 feature film written and directed by Stanley Kubrick, despite it arguably being among the greatest horror movies of all time.
But sometimes a screen adaptation not only lives up to the novel, but breathes new life into it. Sales of Witi Ihimaera's Whale Rider skyrocketed when Caro's adaptation of that book hit the big screen in 2002. Nowadays, it is being used as a textbook in English classes as far away as Kenya.
But without Ihimaera's involvement, it is doubtful the film itself could have been made. He was associate producer of the project, and says it was important to him his story, a Maori story, was told in the right way.
"John [Barnett, executive producer] had the sense that Whale Rider could be an international film . . . a lot of hopes were riding on this project, so we had to get it right. And it was not easy; to make a film adaptation in New Zealand we had to take hold of that whale and push it all the way across the South Pacific, it felt like." It also meant smoothing over resistance to Caro, a Pakeha, telling a Maori story.
"There are some writers whose experiences with film have not been very good at all, and there are some books that have been made into movies which I do not think do justice to the books. It's kind of a dilemma, and I try to make it less of a dilemma by getting involved."
Writer Lloyd Jones was a script consultant on the film version of Mister Pip, but that was where his input ended.
He says while it was "terrifying" watching Mister Pip for the first time, he loved what director Andrew Adamson had done with the film.
"Strangest of all, I think, was seeing the physical embodiment of characters," he says via email.
"Here they were in flesh and voice and clothed and sometimes not quite how I had imagined them. But that is how it is for any reader who in the course of reading creates for themselves the image of the character. It took me a moment to adjust to the idea of Hugh Laurie as Mr Watts, but only a moment. Now I cannot imagine Mr Watts looking or sounding any other way than Hugh's Mr Watts."
As hard as it might be then, maybe the answer for readers - and viewers - is to treat book and film as separate works of fiction.
As Boyens says, if Lord of the Rings had been a flop, JRR Tolkien's works would have remained fantastic novels.
"Books are inviolate, you really cannot destroy them - if it's a great piece of literature it will be a great piece of literature forever."
Five books to read before they become movies in 2014
Dark Places - Gillian Flynn
Murder, class issues and satanic cult hysteria in rural America - what could be more thrilling? The cast includes Charlize Theron and Nicholas Hoult.
This is where I Leave You - Jonathan Tropper
A dysfunctional Jewish family are forced to fulfill their dying father's final wish and observe a religious holiday together. The film stars Jason Bateman and Tina Fey.
All you need is Kill - Hiroshi Sakurazaka
A military recruit finds himself stuck in a time loop, fighting the same battle against alien invasion every day. Tom Cruise and Emily Blunt star in the adaptation, retitled Edge of Tomorrow.
The Hundred Foot Journey - Richard C Morais
A displaced Indian family opens a restaurant in small-town France, but must contend with the Michelin-starred eatery across the road. Helen Mirren will star, with Steven Spielberg and Oprah Winfrey producing.
The Maze Runner - James Dashner
Potentially the next Divergent, Maze Runner is yet another young-adult dystopian science fiction trilogy, this time featuring teenagers with telepathy. Starring Thomas Brodie-Sangster and Dylan O'Brien.
- Sunday Star Times