When you have appealed as far as possible, you can consider appealing to the U.S. Supreme Court. If you decide to appeal to the Supreme Court at this stage, the next step is to prepare a petition for certiorari. This is the document the Court will read in order to decide whether to hear a case.
Commercial applications have an even broader spectrum of change-out frequencies. Air filters in restaurants are commonly changed every 4 to 8 weeks depending on the customer traffic and filter type.. Retail chains, strip malls, and other small businesses vary, but usually are in need of a change every 12 weeks.
Once your filter hits 20,000 to 30,000 miles of use, you should check it again and be ready to replace it. Some air filters may last until 50,000 miles of use or more, but you should never wait that long to inspect your filter.