Issue
You'd like to know when you last authorized the Salesforce credentials used by Heroku Connect, and re-authorize if needed.
Resolution
From your Heroku Connect dashboard, go to Settings and then Manage Salesforce. You'll see your Salesforce username and the last time the user was authenticated.
To re-authorize, click the "Authorize Now" button on that page and the "Authorize" button on the next page. This will bring you to a Salesforce login screen where you can type the username and password. Upon successful login, your re-authorization will be complete.