Item Category Change and its related effects

Hello,

My client is on v9.2 PUM24. They currently have lot of Inventory Items that are not efficiently mapped to their item categories/family/group for the business they are in and want to clean/add new categories/family/group and add the same to Items. I did not see any effective date so if I change these values on a current Item, does it cause any issue?  I thought I could use effective date logic but Item definition page does not have one hence this question. My client has close to 30,000 items under various BU's.

Thanks

Balaji Tirumala