During a new pitcher's warmup pitches....

[DG]

Before the game starts I watch warmup pitches 1-4 from the 3b line, then watch 5-7 from behind the catcher, all in the slot for a RH batter and then tell the catcher to throw it down and get out from behind with my brush ready to dust off the plate. I don't do this again the bottom half, and I don't know anybody who gets behind a mid-inning substitute pitcher to watch him throw.

I wouldn't think anything of you getting behind the catcher for any number of pitches prior to the start of the game, But I would give it a thought if you did the same in the bottom half of the 1st and if you did it for a substitute pitcher in a middle inning you would be doing something I never see (hint). What I normally see is the PU with a notepad out writing down changes while the substitute pitcher warms up. Get a couple of extra balls if you need them while he is warming up.