Hello SeniorAccountant,
Welcome to the Community. QuickBooks Desktop is a versatile program that enables you to get your work done in less time. I'm happy to learn you're using the program so you can accurately manage your inventory. Rest assured, I'll be glad to share more info so you're on the right track.
Updating your inventory will affect the new transactions only. The previous transactions will remain at the same cost unless you decide to manually change the cost of the inventory parts. Here's how you can update your inventory parts:
- From the Lists menu, select Item List .
- Double-click the item you want to change.
- Enter your changes in the Edit Item window.
- Choose OK.
If you need to edit multiple items, go to the Add/Edit Multiple List window (List > Add/Edit Multiple List) instead. I encourage you to check out the following article that provides more info on how to manage the inventory in QuickBooks Desktop.
Let me know if this info helps by leaving a comment below. I'll be one message away in case you need additional support. Otherwise, I wish you a great rest of the year!