Contact properties can be filtered in lists and workflows to pick those where a date field is more than a certain number of days in the past or future. But this can't be done with custom company properties. Frequently, attributes are company-level and not-contact specific, like the date a company reached a specific milestone.
For example, I want to start a workflow to all contacts at Customers, where the last Customer Site Review date is more than 90 days old.
