If a player has bad offensive and defensive IQ for the system you're playing, how much will that impact their individual performance and the team's performance and in what ways?

In addition to that, how long will it take to get their offense IQ and defense IQ up to something reasonable if they are both currently a D-?

I think of IQ like unforced errors. Bad fouls and giving up easy baskets on defense, poor shot selection and dumb turnovers on offense. If I can, I try to limit their exposure until they get to C+. If I have to start them due to promises, it means 0 distribution, and shuffling them in the lineup to keep them away from the opponents attack points.

How fast they move up depends a little on work ethic and HS GPA. Smart, hard-workers can get to the C+ range by the middle of the year, with 20 minutes practice time on a set. Guys lower in those categories will still be in the C- range at that point.

Okay cool thanks! I understand it more now.