Arsenal boss Arsene Wenger admits it was "painful" to see big-spending Manchester City raid his squad again last summer.
Wenger ultimately let Samir Nasri, 24, and full-back Gael Clichy, 26, go to Eastlands, following in the footsteps of striker Emmanuel Adebayor and centre-half Kolo Toure, who previously left the Emirates for City. After taking a chance on developing these youngsters with the Gunners, Wenger admits there will always be a sense of frustration at potential lost.
"At the end of the day when you sell a player, you cannot complain after because at some stage you say 'yes we let him go' and you have to do the right thing for the club, but it is always painful to lose players at 23 or 24 years old," he said.
"The financial difference between us and teams like Manchester City has become too big to hope to keep the players for eight, nine or 10 years. Okay, we lost Thierry Henry, Patrick Vieira, other players before, but they had played for eight or nine years at the club.
"It is the first time now that we lose players at an age where they start to produce, like [Cesc] Fabregas and Nasri, who were both 24 years old. That's where you start to become a football player.
"You need to be brave as well to put a player in at 18 years of age, and you need to make room for them, which means you not only need to stand up for the players you put in, but as well you have to kick somebody out."
Meanwhile, ahead of Arsenal's clash with league-leading City, Wenger refused to rule out a move for former captain Henry, who has been training at the club following the end of the Major League Soccer campaign with the New York Red Bulls.
"I do not always master all my thoughts, so [I guess] it has to come through my brain at some stage - but I haven't been concrete on the case," said Wenger.
"I haven't even investigated that. I cannot tell you even if there is a chance because I haven't even made any approach, nor to him nor his club."