The Fair and Timely Citizen Suits Act of 2024 modifies the rules for "citizen suits," which allow private individuals and organizations to sue the government or companies for violations of environmental and wildlife laws. The bill doubles the notice period for filing such lawsuits from 60 days to 120 days under the Clean Air Act, the Federal Water Pollution Control Act, and the Endangered Species Act. It also imposes a hard deadline, preventing plaintiffs from refiling lawsuits or resubmitting notices after 120 additional days have passed following the initial notice period, effectively creating a 240-day total window to file suit. The bill requires federal district courts and appeals courts to render decisions "as expeditiously as practicable," with appellate courts required to issue final judgments within one year of the district court's ruling. The legislation affects environmental advocates, conservation groups, and others who rely on citizen suits to enforce environmental and endangered species protections.