I'm curious how you guys treat old inventory? Currently we are not using the JSS as a true "inventory" module, we rely on it primarily as a management tool.
That being said, I'd like to go through and start purging systems that haven't reported back in a given amount of time. Is there a JSS setting that allows me to do that?
It's not an automated way, but you could save a computer search for the last report date / last contact time (for example, you could say machines that haven't contacted in X amount of days, or haven't contacted since <date>). At the bottom of your search results, you should see a Take Action on Result dropdown box (at least, for JSS version < 9). One of those actions should be to Delete Computers.
+1 to smb_samba's approach, as its really the only way you can do it without resorting to some complicated methods.
If you use something like 90 days as the cut-off check in time for machines to determine if they need to be purged, then you can save the above search and run it once a month and delete anything that shows up there.
We personally don't delete any Macs from our inventory, although at times I wish we were doing that. Our inventory has quite a few stale records that really should be removed. If we ever decided to do it, we may do it like the above. Either that or we would first un-manage them, which sadly cannot be done using a Take Action on Results item, at least not in the 8.x series. Maybe its there in 9 but I can't check on that right now.