BAck to the original post, be careful when you upgrade the youth or traing/medical setups. This stops the development of youth players (you start again from zero) and on the medical side it stops you receiving health packs. The training/medical is less of a problem as these come though very few days, but the youth players are set to zero every time you build, so you have to wait another 21 days (I think) after the build is complete, before you get new players.