The situation my team is in at the time is always going to affect my answer to this question.
Pretty much everything in OOTP is situation-dependent. If you're managing in an "ideal" fashion, you aren't paying a player for his past-his-prime years, especially if you have managed your farm system well and have reinforcements ready or nearly ready to take over.
It is part of the reason why I have a hard time not playing out every game. I feel like a real GM and manager to where I *need* to see what is happening on the field. I can't be a Billy Beane type and not watch the games and then deal with the results.