Asunto: Career Longevity

what factors reduce this stat most? games played? or is just a random factor for all players? is there a way to try and protect this stat on young players? I am forming very much a home grown youth side at the moment will this be possuble or will most have no longevity by the time they are in their 20's?

there is no way to prevent it - it decays every season change. As I understand it the gap between levels grows so for example it takes longer to go from 4->3 than it does from 5->4 and so on.

I didn't think that it could be stopped, however can it be slowed. As in real life would overplaying young talent cause them to have a stunted longevity vs playing games over a longer course by regular resting etc? I have a very young team and it worries me that my youth that are talented will burn out long before they reach where they should if that's the way it works

longevity is certainly affected by injury which in turn can be reduced by investing in a medical centre and staff. its possible that injury is more likely if they play games (assuming they can get injured in a game?) and another relevant point is that as your players play in games their seasonal energy gradually falls which impacts on their training speed compared to players who do not play.
the trade off here is that the players who do not play do not get any experience although they train their skills slightly faster.

if you manage a young team i wouldnt worry about your players burning out. in a few seasons you will still be producing better talented 15 year olds who could replace your older players anyway. This is what i am finding. hope this helps