Occasionally, a certain type of player becomes available for transfer who is such an exciting talent that a manager will snap him up without seemingly considering how he will fit in into his team. Buy now, work it out later.
Faustino Asprilla is a prime example. When Kevin Keegan bought the outrageously talented Colombian striker, for £6.7 million (Dh39.5m) in February 1996, Newcastle United had a settled team and were cruising at the top of the Premier League.
Keegan tried to cram Asprilla into a team already packed with flair players - Peter Beardsley, David Ginola, Keith Gillespie - as well as the settled and prolific centre-forward pairing of Alan Shearer and Les Ferdinand, who scored 49 goals between them that season.
It upset the balance. A mere 15 games later and Newcastle had thrown away a 12-point lead and conceded the title to Manchester United.
Likewise, United's Sir Alex Ferguson bought Juan Sebastian Veron for £28.1m in the summer of 2001, tempted by the Argentine midfielder's superlative range of passing and skill.
But United already had a star-studded midfield - David Beckham, Roy Keane, Paul Scholes and Ryan Giggs. They played 4-4-2 and five into four does not fit so Veron was played out of position, or as the man behind a lone striker.
Despite winning the league title in 2002/03, Veron was deemed a huge flop at Old Trafford and United took a £13m loss on him after just two years at the club.
But, every now and then, there is a player who has such an impact on a team that he moulds the way they perform and becomes the focal point. Rafael van der Vaart is one such player.
Signed in the last moments of the summer transfer window by Tottenham Hotspur from Real Madrid for a knock-down £8m, the Dutchman has been a revelation.
The attacking midfielder has scored seven times in 11 games, but he has also forced Harry Redknapp, the Spurs manager, to change his tactics. Last season, Tottenham were almost always a 4-4-2 team. Now, partly down to the injury to key striker Jermain Defoe, but also in order to accommodate Van der Vaart, Redknapp has switched to 4-4-1-1, playing the Dutchman in the hole behind Peter Crouch, the lone striker.
Not only has it allowed Redknapp to field more of his talented midfield brigade at once, including the explosive Gareth Bale as a left winger, rather than at left-back, but it has also brought the best out of Crouch. Of Van der Vaart's seven goals, five have been set up by the towering forward.
Tottenham have lost just twice with Van der Vaart on the pitch and he was named the Premier League Player of the Month for October. That makes him only the fifth Dutchman to win the award, after Dennis Bergkamp, Ruud van Nistelrooy, Arjen Robben and Robin van Persie.
Van der Vaart will hope he can emulate the first three, by winning a Premier League title.
That might be out of Spurs' reach this season, but Van der Vaart's spur-of-the-moment signing is paying off for Redknapp.