Inventory tracking is pretty much useless if there is not an Asset view or Report on assets with no info or Audit dates more than age X.
How am I supposed to know if there may be assets missing? No one is going to manually click through every asset to find this information.
You could run some custom reports to get the information you need. For example, if you are using one of our discovery tools, you can use the "Last Audit Date" to run a report as shown below. This looks for all devices that have a Last Audit Date older than 01 July 2017. If you are not using discovery, then you can keep any custom date field updated to keep track of the last time a device was audited and then run a report on this as well. Let me know if this helps.