This stuff has probably all been discussed before, but I'm new at this and haven't found the answer anywhere else.  In regards to fatigue, I'm a little confused how it works. 

I have '29 Babe Ruth.  At the end of my last game he was at 95%.  I then checked my team a little later and he had dropped to 93% and no game had been played.  I put him on the bench and looked at my team yet a little later and he is now at 93%.  Needless to say I'm a little confused.  Is he hung over or something? LOL  Does fatigue vary for each player based on how old the player was in the season I had him in? I think Ruth would have been 35 or so in 1929.  Also I have been using him as a DH. I would think he wouldn't fatigue as much as a DH and we're talking about a guy who had 608 plate appearances in '29. 

In this case, would you leave Ruth on the bench? Or would you put him on Rest so that he regains his strength quicker?

He probably went from 95 to 93 when the stats were updated from the previous game.   It takes a minute or two from when the boxscore is generated to when the stats get updated.

Fatigue is only based on PA/162.   Nothing else matters.  If he is on pace to have more than 110% of his RL PA/162 his fatigue rating will drop from 100%.

I generally play guys down to 93% fatigue, it's kinda an arbitrary #.  The drop off isn't linear (except for FLD%) so the difference from 100 to 93 isn't 7%, it is less.  I would definitely advise you to rest guys under 90% however.

Position player fatigue is based solely on the Plate Appearances. It has nothing to do with any players age.

I recently posted a long thread about fatigue that covers most of this stuff; I'll bump it for you.