How to maintain your players several seasons in your team?

[Sparksue]

I train them until the age of 25 years old, most of the times up to 160+% with 25 and so they last until 28-29 at 6 star minimum. But I only do it for offensive players, defensive I replace with 24-26 mostly.

Can I check how much greens do you spend to maintain players at those ages? My understanding is that age 22 or above will be so much difficult compare to 18~21 ages. i have a few players that i wish to increase their skills as they are coming to 22 soon. if there's too much greens - i might have to turn to young players to help me.