The Cook County Assessor's office recently mailed out assessment notifications to properties in Jefferson township in Chicago. The deadline to file an appeal is September 18th.
If your property is showing an increased assessed valuation (which will likely lead to a tax increase) you may want to consider filing an appeal. Condo owners can file individually but appeals are generally more successful when the property is appealed as a whole. The paperwork can be handled by a real estate attorney for a fee.