Training on flawless pitches, changing in immaculate dressing rooms with spa facilities, they could be forgiven for having a sense of entitlement. Courted by agents and sponsors, stardom can seem just a matter of time.
Lower down, apprentice footballers are still asked to clean the boots and dressing room of the first team, but not at the biggest clubs. One United coach, a former first teamer and international, shook his head when one youngster bought the same car as him. What, he wondered, did the player have to aim for when he could already pay for the finest German automobiles?
A loan spell is a much needed dose of reality. Tom Cleverley was stunned in his first game for Leicester City to come up against a veteran professional playing for a win bonus who cared little for Cleverley's growing reputation.
"He was tougher and more determined than anyone I had met and I was in a daze for the first 45 minutes," Cleverley said.
Cleverley was game-hardened at clubs in England but, in the last 15 years, more than 30 of United's past and present players have been sent to Royal Antwerp, Belgium's oldest club. There the teenagers find life in the second tier of Belgium football is anything but glamorous, a far cry from the comforts of Old Trafford and the club's Carrington training ground.
John Cofie is the latest United youngster to cross the English Channel. The striker left on a six-month loan before turning 19 last month and each day has been a learning experience.
"I've had to cook for myself for the first time in my life," he said in the warmth of the players' lounge after a hard-fought victory on an atrocious rain-lashed pitch, where most fans cowered under the pitched roofs of stands built in the 1920s.
"I tried to cook a pizza in the oven when I arrived," Cofie said. "I burnt it. The physio wasn't impressed that I was eating takeaways each night and told the coach, who had a word. He was concerned that I wasn't eating well and invited me to his house, where his wife made me good food."
Cofie's family came to visit recently and his mum left him a freezer full of his favourite Ghanian dishes.
United may be interested in his all round personal development, but Cofie's priority is playing football every week.
"I knew that a lot of former United players had been to Antwerp so I spoke to people like Jonny Evans and Darron Gibson. Then I spoke to my family. We thought it would be a good move for me to be playing competitive football regularly.
"It's better than reserve-team football because it's like a step up from boys to men's football. You play in front of real crowds - Antwerp get around 7,000 for most home games and you are lucky to get 700 at reserve level."
Cofie was born in Ghana, but his father was a clerk in the British Army and the family moved briefly to London when he was nine, before a stint living on an army camp in Germany.
"I played football all the time," he said. "Burnley Football Club would come over once a year and coach the army kids. They would bring their young teams over to play against German sides."
Aged 13, Cofie was asked to play in one such game for Burnley against Borussia Monchengladbach.
"I did really well. Burnley wanted to sign me. My dad didn't want me to live in England alone at 13, so I flew to Burnley every other week and played a game with them."
At 14, Cofie did move to Burnley, alone, where he attended boarding school to continue his schooling. His family managed to relocate to nearby barracks in Preston, Lancashire, to be near their son.
Cofie excelled at Burnley, who boast a fine youth system. In 2007, when he was still only 14, Burnley were approached by Manchester United, Liverpool and Chelsea.
Liverpool offered a reported £250,000 (Dh1,455m), more than United, which Burnley rejected. Burnley were determined to keep their man, but Cofie wanted to move and refused to go to training.
The Clarets felt they had no option but to relent and agree a deal with United, which also gives them a 25 per cent sell-on clause, first refusal on any loan deal and a future friendly game with United.
"I'm glad I joined United," he said. "My dad told me that United was the best place. He said that even if you don't make it in the first team, you will still get another good club and make a good career."
Cofie continued to progress.
"I played in the team which won the FA Youth Cup in 2011 and in the reserves," he said.
The promise of the 6ft striker has been recognised at England youth level but, despite encouraging words from Sir Alex Ferguson, Cofie is under no illusions how difficult it will be to break into the United first team. He looks to players like Cleverley for inspiration.
"Tom was on loan for three years at three different clubs, but he improved significantly each year. That can be me. I've only been in Belgium for a month and I've learnt so much. I'm learning about the mental toughness required, how to lose as well as win. I'm learning little tricks, how to win the ball in the air by jumping first and maybe using a bit of an elbow. You have to do that against men or you don't win the ball."
He has learnt that not all footballers live a life of luxury. The captain, Karel de Smet, for example, is a journeyman with a young family who drives 160 kilometres each day to training. He stands up in the dressing room before most games and highlights the importance of the win bonus.
"It makes me realise that most footballers have a financial burden on them, unlike myself and the first-team players at United because they are so well paid," said Cofie. "I now think about money in a better way than I did."
Cofie is close to several of United's first teamers, particularly Anderson and Danny Welbeck.
"I want to join them," Cofie said. "Danny has been in the same position as me. He tells me to work hard, stay out of trouble and keep my head down. It sounds obvious, but if I got in trouble then word would quickly get back to Manchester and the boss would not be happy."
Cofie's ambition is obvious. He plans to stake a claim for a spot in the first-team squad for next season when he returns to Manchester in the summer.
"I'm just going to do my best and get a new contract at United," he said. "If I'm not pushing to get in the first team then I'd like to go on loan somewhere in England."
For now, the reality is more prosaic.
While United go to Tottenham Hotspur on Sunday, Antwerp play Waasland-Beveren in a game they need to win to keep their promotion hopes alive.