Execute a Powershell script when the user certificate changes

Hi, 

I have a Powershell script that make use of user certificates in a particular user's certificate store. Whenever there is a change to the current certificate, I need to automatically run this script. Change in the sense of, 1) The current user certificate expires and get a new certificate. 2) The user renew the current certificate. 

What approaches that I can take in order to achieve this ? 

Thank you.