What trade-offs are involved in each of these aspects of inventory management?

What trade-offs are involved in each of these aspects of inventory management?
a. Buying additional amounts to take advantage of quantity discounts.
b. Treating holding cost as a percentage of unit price instead of as a constant amount.
c. Conducting cycle counts once a quarter instead of once a year.

Who needs to be involved in inventory decisions involving holding costs? Setting inventory levels?
Quantity discount purchases?

How has technology aided inventory management? How have technological improvements in products such as automobiles and computers impacted inventory decisions?