I do kind of wonder what Vader's down-time looked like. I'm sure he probably didn't have much of it, and probably didn't want it, free time would be time to think and remember all kinds of painful memories.
But once in a while I'm sure he found himself with a few minutes after wrapping up a mission early, with his meeting with the emperor not scheduled for another 15 minutes, not enough time to get to his chamber to take off his helmet and meditate, no suitable training facilities handy, no underlings around to intimidate. Nothing to do but hang around in Sheev's waiting room. Does he watch pod racing on the holonet? Does he flip through a copy of Popular AstroMechanics or Imperial Geographic? Does he whip out a GameYoungling and play some space Holo Tetris?