We seem to be having issues lately with holds: when to place them, when to send a check on collection in lieu of doing a hold, and when to just simply refuse the item for deposit (and how you explain all this to the customer).

This was in another post by Ken_Pegasus and it hits the issue we are having perfectly:

Does anyone have good training material, or a link to good resource material on this topic that covers this fundamental understanding?

Not that I know of. You only place a hold in situations in which you will know if the check will not be paid within the hold time. Which for simplicity sake, I would pretty much limit to situations when the only question is whether the check is drawn on non-sufficient funds. Anything else, I would train people to send for collections or refuse the deposit.