First up, former teen heartthrob Donny Osmond, who thinks the 1D guys will be done and over in a year and a half.
In a recent interview with WENN, Donny shared his thoughts on how much longer the 1D phenomenon can last, saying, "One Direction are huge and there is real talent there but they have a year, year and a half left. We all know it and I think they know it."
He also thinks that Harry Styles will be the breakout solo artist from the band, saying, "But keep your eye on Harry, he has the work ethic. I learnt the hard way that you can't just 'decide' to be a solo artist, but he will make it work."
Meanwhile, Simon Cowell is worried that 1D could be heading for burnout, given their break-neck schedule of recording and touring, explaining to The Sun (via PressParty): "They can't carry on doing the amount of stuff they've been doing for long because they'll burn out - it's a high-class problem."
He added, "But they don't complain about working hard."
Simon seems to think they have a bit more longevity, saying, "They're going to be around as long as they want to be, because they're talented and good writers - and they understand their fans."