How much do players' value drop every new season?

[yawnyawns]

Hello everyone, I'm pretty new to this game and I have a question.

I'm about to head into my third season and I'm clearing stock to raise funds for the shopping spree I plan to have when the new season starts. I sold almost all my subs with value and now I'm left with choosing which young first teamers I want to get rid to get cash and which I want to develop further. My squad now has 18 players and I guess I can sell a couple more with 3 games remaining. My placing in the standings is more or less guaranteed so I don't need a very strong team.

So my question is, how much do players' value drop after each season? especially the young ones.

I'm ready to sell some 18-22 year olds and in my level, they are worth about 600k-1 mil with ratings between 17-21. (3-4 stars)

And how do you guys decide which young players to keep? Currently, I have 4 19-21 year olds with ratings above 22 (4-5stars, including my best player "a local born and bred midfield powerhouse/top scorer&assist/future captain&legend = steven gerrard") and I plan to keep these 4. Or should I sell ALL my young players (below age 22) and just buy older, higher rating players and only start to invest in young players in higher divisions? (maybe level 4?)

Lastly, how many seasons did your young players last whom you had since level 1?

Oh ****, I wanted to just ask 1 question