40
Player, the keeper is normally #1
Kanu still plays for his club Portsmouth.
Never he still plays, check out Vasco De Gama
At about after 4 or 5 years they retire.
Normally the left back or full back wears number 3. He is normally left footed.
Just about every team has a player with the number 5, normally a wing-defender.
You can be a pro soccer player as long as you are good, fit and playing well. Most players retire in their thirties when they find younger players, just a little bit faster, are taking their jobs.
Because he's old.
A soccer player.
I'm not very sure. But there was a 19 year old I heard, who was injured on his debut, and after the match, he retired from FOOTBALL, not soccer. Stanley Matthews retired from professional football at the root age of 50.
Soccer Player mate
Persistent injuries and advancing age.