Antonio Conte has urged Tottenham to be more careful in the transfer market after suggesting the club was guilty of making "mistakes in the past".
Spurs allowed Tanguy Ndombele, Giovani Lo Celso and Bryan Gil all leave the club on loan in January, while Dele Alli joined Everton on a permanent deal.
Alli undoubtedly flourished for a time at Spurs, but Lo Celso and Ndombele have so far proven to be expensive flops since joining in 2019.
Lo Celso, signed for an initial £27.8million (€32m) from Real Betis, was shipped off to Villarreal with a purchase option, while Ndombele – a club-record signing at £55m (€63m) – was sent back to Lyon, who retain the right to buy him for a reported €65m (£54m).
Spurs do at least appear to retain hope for Spain international winger Bryan, 20, whose temporary switch to Valencia does not include any purchase clauses or obligations.
However, Conte's general appraisal of the situation does not reflect especially well on any of them, nor those in charge of transfers at Spurs.
"Usually you buy players to reinforce your team," Conte told reporters on Friday. "But if you send on loan after two or three years, it is strange.
"It means that maybe in the past you have to see what you did and maybe to understand that there were some mistakes in the past.
"We have to pay more attention in the future when we go into the market. It becomes a fundamental importance if we want to enforce the team, otherwise you drop the quality of your team."
Tottenham were active with incomings as well, with Rodrigo Bentancur and Dejan Kulusevski joining from Juventus. Spurs sporting director Fabio Paratici previously signed both players during his spell in charge of the Bianconeri.
While neither player ultimately fitted the bill in Turin, Conte appeared excited by their respective arrivals in north London.
"We are talking about two players who are the right prospects for the club's philosophy, young players, talented players to develop and improve to then become important players in the future," he said.
"They have the right experience, Bentancur, for sure, has played many games for Juventus, Kulusevski as well. To be able to sign these two players was good, because they complete our squad.
"We needed to add another player in the midfield. We played with only three midfielders – [Pierre-Emil] Hojbjerg, Winksy [Harry Winks], [Oliver] Skipp.
"We needed to add another player, and we added a good player. Not only to add one player, but a good player.
"Rodrigo has a lot of space for improvement, he played for his national team, 200 games [for Juve and Boca Juniors] despite his age; he's only 24 years old. He's won in Italy. Yes, a good signing for us."
Winger Kulusevski had previously been tipped for a big future at Juve when initially signed from Atalanta amid a breakthrough loan spell with Parma in 2019-20, the year he was named Serie A's Young Player of the Season.
Conte is confident Kulusevski's versatility will be an asset, and he is even confident the wide attacker could operate effectively as a wing-back.
"Dejan has the characteristic to play, in my mind, behind the striker, one of the two number 10s we have behind our striker. At the same time, he has the capacity to play as a wing-back, on the right. He also likes to do this because physically, he's very strong, he has good quality," Conte said.
Conte was said to want to use Adama Traore, another winger, as a wing-back before he chose Barcelona over Tottenham.