Filing the appeal itself is only the first step. Once the Board of Revision receives it before the deadline, the real work is assembling evidence, sold comparables, documented factual errors on the city's property record, before the hearing date that follows.
A common mistake is treating the deadline as flexible because the tax bill itself does not arrive until later in the year. The appeal is against the assessed value on the spring notice, and only that value, taxed at 80 percent, flows through to the fall tax bill on a separate timeline.
If you are close to a deadline and unsure whether your assessment is actually out of line, a quick market check is faster than guessing. Get your hand-reviewed valuation from Joel Dyck.