There have been some incredible academy stories from over the years with Trent Alexander-Arnold flying high at Liverpool, and Chelsea funding multiple Premier League sides with their talent on loan.
The ideal situation for any club is to have streams of talent coming through in every position, and the stars are either used in the first-team or sold for a hefty price.
Southampton were the old churner of world-class talent, with Alan Shearer, Gareth Bale and Matt Le Tissier climbing through the ranks at St Mary's, but the goalposts have somewhat shifted since then.
And a list of the top ten most profitable European academies have been released, with Chelsea and Liverpool leading the way for the Premier League.
CIES Football Observatory have observed which clubs worldwide have generated the most income from sales since July 2015 from academy graduates.
Figures are only accepted if players have been at the club for at least three years between the seasons of their 15th and 21st birthday, and Chelsea and Liverpool are the only Premier League sides within the top ten.
Benfica are clear at the top with a profit of £313million, which is hardly surprising when stars such as Joao Felix, Ederson, Renato Sanches and Raul Jimenez coming through the academy before being sold for large sums.
The Portuguese side are just ahead of Real Madrid, who have Alvaro Morata to thank for a large proportion of their profits, but not as much as Kylian Mbappe, who makes up 63 per cent of Monaco's academy profits since 2015 alone.
Chelsea are the highest ranked English team in the rankings as they sit in eighth position, but it's perhaps not a fair reflection of the success of their academy, as they have only just started letting their stars go.
Tammy Abraham and Fikayo Tomori make up a large proportion £175m profit, but with stars such as Billy Gilmour, Conor Gallagher and Armando Broja thriving out on loan, they could shoot up the rankings with future sales.
Liverpool sit in tenth, and have Raheem Sterling to thank for 41 per cent of their total £142m figure due to his mega-money move to Manchester City.
Jordan Ibe was also a big hitter, but the Reds tend to hold onto their stars when possible, as seen with the likes of Alexander-Arnold over the past few seasons.
Chelsea's academy is arguably the greatest Premier League youth set-up in the modern day though, as after being criticised in the past for their loan system, they appear to have got the balance right.
Mason Mount, Reece James, Andreas Christensen and Callum Hudson-Odoi are all academy graduates that are thriving in the first team, and Trevoh Chalobah is also becoming more of a senior figure at Stamford Bridge.
Aston Villa found themselves abnormally high in the overall rankings, but that's because they had the most influential sale on the list, with Jack Grealish's move to City accounting for 89 per cent of their £110m profit.
Manchester United need to up their game though, as they were almost too low down to even be listed, as the club have only taken in £54m since 2015, with goalkeeper Sam Johnstone their biggest sale.
