Training and development
How players actually improve: minutes and performances on the pitch, plus one off-season pick per club.
Players develop by playing. Minutes, match ratings and age decide where a career goes, and the whole season is settled once, at the end of it. There is no weekly training plan to keep on top of.
Minutes get him on the pitch, performances move him
A young player needs real minutes before a season counts for much, but what he does with them matters more than how many he gets. A good season at half the minutes beats an ordinary one played every week. Leave him on the bench and he stalls either way.
A better training facility makes every good season count for more, for the whole squad. It does nothing for a bad one.
Past 30 a bad season costs him wherever his rating is built, whatever position he plays. The running goes on top of that, so pace, stamina and strength are the first things you see slipping on an ageing player's profile. Regular football slows the slide in his early thirties, but from about 34 even an ever-present starter loses a few points every season.
The off-season pick
Between seasons each club picks one player and one thing to work on: a single attribute, or a conversion to a neighbouring position. It is a roll, not a guarantee. Younger players take coaching more readily, a player close to his ceiling has less left to gain, and a better training facility improves the odds. Some summers simply don't click.
Position work follows fixed paths: a CM can aim at DM or AM, a ST at AM, LW or RW. Keepers can't retrain into an outfield role, or the other way around.