Gather allows you to add important dates and info such as Invoice and PO #'s as well as ordered, shipping, receiving, and install dates. 

To add this info to an item open the item and select the "Status" tab. In this section, you can enter a date manually or by choosing a date from the calendar. You can also add a note to each line if needed. 

Alerts for these dates can be sent to you via Email or within Gather. Please see this article to learn how to set your notifications.