Or you could look into adding Avalara AvaTax and CertCapture functionality to your business systems.  Maybe check with your local consultant or Reseller of Record for Sage 100 to see what suggestions they have. 

Depending on volume, I'd think an automated report might do it, using software like Sage Alerts or Visual Cut, to let you know when an expiration date is nearing / passed... for manual edits.

You can also try to script something in Sage, but that gets complicated quickly.

Can you tell me more about Sage Alerts?  Is it an ancillary product?

It is an external reporting tool, sold separately, with a large feature set.  Google can tell you more, and so can your Sage partner / reseller.  (It's basically a Sage branded version of the Knowledgesync software). 

For a simple daily alert like this, something like Visual Cut (3rd party, and much more cost effective) is what we use for many of our clients.

Thanks Kevin, I'll check both of those out!