You can find the age of your collection in Web Management Reports. Under the heading COLLECTION, select Age of Coll and then the REPORT select Age of Collection. It does take quite awhile to run so don't expect immediate results.
Thank you Karen. However, in Web Management Reports, I do not have a Collection heading. All I have are Circulation Activity Reports, which is broken into All Circulation Activity, Cross Circulation Tabs, Patrons, and Checkouts. Where do I find the Collection Heading you are referring to?
I have some of Brent Searle's Age of Collection SQL queries where he grouped the results by general info, mat type, classification, and a few others. They are based on LC call ranges - not sure if that is a factor for you. They do take a bit of tweaking to get your system to recognize them, but wow are they great.