It takes time to create a buzz around a festival show, and soon the run is over. Bringing a hit back can give companies a publicity head start – and a cash boost to their next venture. But there’s no guarantee of glory second time around.

“Assumption is the mother of all cock-ups. We can’t assume that it will be a golden ticket,” says Jimmy Fairhurst of Not Too Tame about the return of the company’s 2014 word-of-mouth hit Early Doors to the Edinburgh festival this summer. Performed in a real pub, it’s a lovely, unassuming show and has been a deserved success on tour. This year, the company are also bringing a new show, Electric Eden, to the fringe. Like Early Doors, it’s a piece of popular theatre that gives ordinary people a voice. “We make theatre for people who think theatre might be too polite for them,” says Fairhurst. “Like Pete Postlethwaite said about the Everyman: ‘We’re cheap but we’re not shoddy.’”

Not Too Tame are hoping to cross-fertilise their audience, to use the return of a proven hit as a cushion to help spread the risk of Electric Eden. But Fairhurst is right to be wary of assuming that Early Doors is a certain banker for them. The fringe can be a fickle place. Just because something is a hit one year doesn’t guarantee that it will capture punters’ imaginations and wallets next time round.

The days when Hull Truck’s production of Bouncers was a dead cert for the company year in and year out are long gone. Today’s fringe is massively bigger and more competitive, and offers audiences way more choice. The new is often prized far more than the tried and tested. When a show returns a second or third time to the festival, it is unlikely to attract the same interest from the press and bloggers or to attract the attention of awards committees.

Of course there are shows that are successful year after year: the Iranian sleeper hit White Rabbit, Red Rabbit returns to Edinburgh for the fifth time this summer, but the format of the play – in which a performer is given the script sight unseen – means that it’s different every time. It bears repeat viewings. Every Brilliant Thing is back at Paines Plough’s Roundabout tent at Summerhall for the second consecutive year, and given its huge international success it may still be there next decade. But like Fairhurst, Paines Plough’s James Grieve isn’t banking on anything.

“We are never complacent. We hold our breath every year at that moment at the end of July when we look at the advance sales figures, and we always go: ‘Wow, that’s not looking great.’ But Edinburgh audiences book very late, and our guiding principle is that we will bring something back if we think there is still an audience for it. During the second half of the run last year there were huge queues for returns for Every Brilliant Thing every single day and as long as we think there’s an audience for it we should do it, not least because we are really proud of it.”

There’s another reason too. Like many companies, Paines Plough work within a mixed economy. A show such as Every Brilliant Thing can provide the financial return needed to support new work in Roundabout. This year’s Roundabout lineup includes Lemons Lemons Lemons Lemons Lemons, Sam Steiner’s debut play about a world in which the government limits citizens to 140 words per day. That show had audiences queuing for returns at Zoo Southside last year. Putting it in Roundabout not only allows a far greater number of people to see it, but is also an affirmation of faith in a writer and company who Grieve describes as “so young they really have no right to be so accomplished”. He hopes it will help pull a younger audience into Roundabout.

“One of our jobs at Paines Plough is to find and nurture the people who will write the Every Brilliant Things of the future,” says Grieve. “We reckon Sam Steiner could be one of those people, and so by bringing Lemons back in a bigger space, we’re supporting that.”

Last year, Joe Sellman-Leava of Worklight won a Fringe First award at the end of week two for his show Labels, a quietly impressive one-man show about his experience of prejudice while growing up and the casual racism that he and his family encounter on a daily basis. Labels had a 55-seater space in the Pleasance where it played to 68% capacity, regularly selling out towards the end of the run. One of the problems in Edinburgh is that companies have to budget for the fact that they are unlikely to fill all seats in the first week or so of the festival, but if the show captures the public imagination they can’t fulfil demand later because of the limited run in a limited capacity space. Bringing a show back is a way of trying to capitalise on that past success.

This year Labels will be in Pleasance Beside, which has 80 seats to fill. Sellman-Leava knows he’s taking a risk, but it’s one he is going into with his eyes wide open. He has worked on the show since last year and feels it’s stronger. Being back in Edinburgh helps keep Worklight’s name alive on the fringe (with audiences as well as those crucial venue programmers) until they can return with a new show next year. The company is also putting more money into the marketing and advertising budget to spread the word. As Sellman-Leava says, in the post-Brexit climate in which hate crimes are rising Labels is “more relevant than ever”.

But judging when the fringe has already had too much of a good thing can be a real skill too. Fringe favourites Les Enfants Terribles – whose new version of the hugely atmospheric The Vaudevillians will play in Edinburgh this year – had a big hit in 2012 with The Trench. They returned with that show the following year, and Les Enfants’ James Seager says it was useful because it allowed them to “change it and improve it”. But even though the Pleasance was eager for the company to bring the show back again in 2014, Seager demurred. “Of course we were tempted but I really thought it might be overkill. It’s better to leave people wanting more.”