For all the money clubs spend on academies and developing players, some slip through the cracks.
Not every star is built in-house. Some players fall down the leagues and have to rebuild themselves in non-league football.
Many fall out of the game altogether, but some show their worth and begin a climb back to their rightful level.
It's an unlikely journey, of course, but plenty of players have proved that it is not impossible.
Below, we take a look at a starting eleven of players who rose from non-league football to make a name for themselves in England's top tier:
Before moving to Manchester City in 2006, Hart made his debut for his hometown side Shrewsbury in the Conference a day after his 17th birthday. Has gone on to win 70 England caps and win two Premier League titles.
The former Liverpool man is the only player to have played in the World Cup, UEFA Champions League, UEFA Cup, Intertoto Cup, all four levels of the English league football and the Football Conference. Wow. He started at Welling United, but he would go on to win the Champions League.
10 years ago, Antonio was playing at Tooting & Mitcham United. Now, he is one of West Ham United's most important players after moving to the Premier League in 2015. He was the Hammers top goalscorer last term with nine goals and even earned an England call-up, but he is yet to get on.
The Welsh international started his career at Hendesford Town before gradually climbing the leagues with first Stockport and then Swansea. After making it to the top-tier via promotion with the Swans, Everton splashed £12 million on the 70-time international last summer.
What a meteoric rise. Smalling made an impression while playing for Maidstone United as a teenager and it prompted Fulham to take a chance on the youngster. He did so well in his 13 league appearances for the club that Sir Alex Ferguson paid around £7 million to bring him to Old Trafford. Since then, he has won 30 England caps and has winners' medals for the Premier League, both domestic cups and the Europa League.
One of the funniest footballers in recent memory had humble beginnings. The talented playmaker started with Corinthian Casuals before moving to Dartford in 1997. He would then play for Gravesend and Northfleet before finally getting his break with West Ham. He made his way to the Prem via promotion with Wigan and enjoyed great success with Fulham before a knee injury ruined his time with Hull. Was called up to the England squad but never played.
The 31-time Democratic Republic of Congo international started out with Hillingdon Borough before climbing the leagues and arriving in the top-flight with Crystal Palace six years later. He signed for Everton last summer in a deal worth £25 million.
Football's resident hardman turned Hollywood actor started out with Wealdstone before becoming a member of the infamous 'Crazy Gang' with Wimbledon. His first taste of Premier League football actually came with Chelsea and he nabbed nine caps for Wales.
The most romantic story of them all. Vardy had three non-league clubs before Leicester took a punt on him back in 2012 and the electric forward has not looked back. He broke the record for scoring in successive Premier League games last season en route to winning the whole thing and then he went to the European Championships with England.
Sir Les started his career with Hayes, but a move to Queens Park Rangers established him as a dangerous force in the top leagues. He finished his career with 149 Premier League goals and 17 caps for England. He also scored the 10,000th goal in Premier League history.
After playing a handful of games for Greenwich Borough, Crystal Palace signed Wright in 1985. He would go on to become Arsenal's all-time record goalscorer - before a certain Thierry Henry - and he made 33 appearances for England.
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