Here are all of the responses I received regarding if/when overdue items are deleted:

We do not delete an item from our inventory until it is paid for. If the item is in demand and overdue, we may decide to buy a second copy of the item. However the first copy is not deleted from the patron's account.
We generally don’t delete items until they’ve been paid for, because then there would be no record to refer to if the patron inquires about the lost item. I’d be interested to hear what other libraries say!
We’re an academic, so we don’t delete a lot of records. Suppress, yes. We do a number of searches, usually at least six, over a year. Many of our items turn up in this time, especially around semester beginnings and endings. It’s a mystery where they disappear to. About a year is the range for items lost or missing within the library.
Overdue and lost by patrons is another story. We usually follow-up within 30-60 days, but even so we don’t delete the record itself. We do update and suppress as appropriate. We have had discussion about this in the past. One of our motivating factors is we need to do a complete inventory of our 1 million plus holdings, and are working on this. Also, since we are an academic, we may reorder the same title, or link it to an online version through Hathitrust, etc.

Because we pay for every record on the system (Sirsi-Dynix via Valley Library Consortium) we elect to delete items when they have been LOST, TRACE or ITEM MISSING for over 1 year.? This includes overdues as their status changes to LOST after 42 days overdue.? We do this knowing that the system retains the information on the borrower records.? If an item is no longer readable due to damages I delete the item record sooner.?
We wait approximately one year from when the item is marked lost. An item can be marked lost after a conversation with the patron where they indicate it was damaged, destroyed, or stolen, or at the end of a 6-weeks' process to recover overdue books. The parameters for our "lost" purge report specify all items marked lost for more than 1-year. In theory, I'd run this report several times a year. In reality, I often forget until it comes to compiling year-end statistics, so some lost items can remain in that state for up to just shy of two years.
We have a monthly automatic report that runs for items that have been lost for more than 3 months that goes to the department heads, who have the option to re-order items on the list. If re-ordered, the item is deleted from the system and the patron still has to pay for the item. I believe we chose 3 months because the overdue items go to lost after about a month and they would've gone to collection at that point (I believe after two months being lost) and if they had any intention of returning them, they would have by then. If not paid for, I believe that they are deleted after a year when we get rid of lost, trace and missing items from the system (which happens on a regular basis) and it stays on the patron's record until the item is paid for. If paid for, they are deleted from the system right away.
If an item has been billed, then it isn't ever removed until the patron pays for it- if ever. For missing items, I usually give us a year to find them. Sometimes it didn't get checked out, sometimes we find it in a strange spot, with two locations- sometimes it is in the wrong location and sometimes it just never shows up. So when a year has passed, it is still missing, then I withdraw it.
After 180 days, we move long overdue items to Discard. Shortly after, a report runs that removes the discarded items. The items still remain on the user accounts as assumed lost bills and in the Extended Info tab, where you can find title and barcode information.
Once a year I run a report on overdue items and delete (or replace) those more than a year overdue. (For example, earlier this month I deleted books due in 2016). I do keep paper records for these delinquent patrons as well as flag their cards in the circ system. After 10 years, we delete the patron's card and give up.
· We do not delete records for overdue items, regardless of how long they are overdue. Records for billed items are not deleted unless both of the following conditions are met: 1) We have received payment either from the borrowing patron or (in the case of ILL) borrowing library; and 2) We decide to not replace the item in question.

Savannah Shilton
Director
Putnam District Library

327 N. Main St.
PO Box 920
Nashville, MI 49073
Phone/Fax: 517-852-9723

Honoring the Past, Serving Today, Preparing for Tomorrow
www.putnamlib.org