I have read or heard somewhere that sperm aren't as active after a man has taken a shower or bath, since they are warm. Thus, why the balls are lower and away from the body so they can be cooler.
Men produce like thousand of sperm a day so I wouldn't imagine that they are old or dead (never really heard of that before). And I would say that the best way to get the most sperm would be to have the mens first ejaculation of the day (if you are trying everyday). But then again, I am no expert.
