IFEBP > ACA University > Timelines and General Resources > Timelines Timelines The provisions of the Affordable Care Act (ACA) have been implemented over several years. Some provisions became effective upon enactment of the law, but many become effective in stages, beginning in 2010 and continuing through 2020. Timelines Health Care Reform Timeline, Cigna, 5/2/2017 Lists health care reform rules as they take effect and change year-over-year