I go by performance to be honest. One of my now 32yo led the team just two seasons ago in goals (and tied the season before that) without any additional training just for him. I had to switch his position but the switch brought goals. My thinking is that the game has hidden designations for some players and they continue to perform even after their skilllevels and ages would say they should not.
As for the other 32yo while his performance was not as good I noticed that the team seem to play well with him as captain. Again, all I can really measure is that I won several CLs with him as captain. I certainly had better, younger players but the team did not “appear” to play as well as when he was in. So I kept going with a hot thing.
Now neither of them outperforms their teammates (not last season either) and they sit.
Honestly I am not sure the science behind my methods but I do think there are hidden settings. In this season, though I am using the same formation as the last two or three seasons, one of my attacking middies is racking up goals at greater than one per game while the other has completely fallen off. Statistically the one that has dropped off is better than the one on fire. Again, my guess is that some hidden parameter says this is a career year for the one at least. Otherwise I have no way to explain how two players, who have played about the same the last several seasons, all of a sudden have two very different years.
I assume these hidden player or season settings are something like the random game settings where one moment my team is lighting it up and then against the same team we can't hit the broad side of a barn.
Would be interested in other player's thoughts on this...