It is good and applies to have a routine as well.
Get the guy physically ready and, hopefully, in a good mental place as well.
Nothing makes me battier than watching high school guys warm up and them talking between every pitch with the catcher or the other pitchers....whats going on after the game, social stuff, the MLB game last night....all nonsense. Or guys that want to work on "new" pitches while they are warming up.
Well, there is one thing that makes me crazier. A coach calling a kid in to pitch with no warm up. The kid grabs his glove and gets 8 warm up throws on the mound and is supposed to be ready. To me, this is mostly bad organization by the coach. I have seen one program where I live (not surprisingly the most successful program) have 2 or 3 pitchers start a routine mid first innings....two guys, usually a right and a lefty will take a jog, start with bands ect. By the 2nd inning, playing catch, getting loose. Even if the starter is cruising by the 3rd they are pretty ready to go. If the starter starts to struggle the coach has a couple of guys loose and warm in the pen. As soon as one a guy goes in to pitch, next man up starts the routine. This means the coach has his pitching rotation set ahead of time. Crazy.