Retention Periods set the audience's time window. A 30-day audience includes people who took the action in the last 30 days, and it updates itself automatically in Meta. You can select several periods at once (1, 3, 5, 7, 14, 30, 60, 90, 120, 180 and 365 days), and each audience type you select is created once for each period. The preselected defaults are 7, 30 and 90 days. Keep Meta's limits in mind: engagement audiences (Instagram, Facebook and video) accept a maximum of 365 days, and pixel-based website audiences accept a maximum of 180 days. Meta rejects periods above the limit and the item shows Error in the list, but the other audiences are still created.