when managing a average team, i sign who i feel i need to push the team further up the league, as well as prospects.
Once im the top team in the league ill only sign youngsters to bring through, or if i have a bad season ill sign a star to spice things up again.
I try to sell players when they hit 30 to make a bit of money back unless they are a legend at the club.
on fm07 - i had the leeds starting line up of players that i signed at the age of 21 or under and went on to dominate for years, when the players start hitting 27/ 28, then i focus on signing there long term replacements, and bring them through slowly, so by the time my main player hits 30, my youngster is ready to take over.
Even if i dont need a player, ill still sign him if he looks a great prospect because you never know when your next world star will develope. Players who dont make it into my first team, i sold on for a good profit.
On that game, in the year 2021, i looked at the england squad, 4 were my players, another 18 were players who i had at one point and sold on. the starting 11 either played for me or used to but never made my first team.