I'd always say to joemktgson: "You practice to practice, and you practice to play."
Here's what I meant by that...
Team practices are generally insufficient for position player: too many players = not enough reps. As a result, a player cannot improve at the rate required to continue to grow and succeed because baseball is a game of repetition, e.g., number of swings, number of grounders/flies, number of throws, etc. The math proves this to be correct: assuming 7 infielders, a player will receive 1/7th the number of reps during X time vs. on their own for the same X. So if improvement is desired, it doesn't make sense to rely on improvement solely during practices when X time on your own yields a multiple of 7 more reps.
So what's the purpose of a team practice? Outside of team plays such as cuts, DPs, bunting plays, etc., the practice focuses on the individual and how the individual is performing relative to his peers. And why is that important? That's how the coach will determine playing time. As a result, it is paramount that the player goes into the team practice ready to perform at the highest level so as to secure playing time.
And how does your son perform at the highest level? PRACTICE! And that's practice on his own. The player practices on his own to be prepared for team practices, and the team practices will determine playing time. "You practice to practice, and you practice to play."
I'll post practice options next time around.
Joe