How long can a Reserve unit be activated?A reserve unit can be activiated for up to two years. If the unit served the full two years, they can only be reactivated upon receipt of a new executive order. There is no set time between the end of an activation and the start of a new activation order. Personnel may only serve two years under the current executive order. If they didn't complete two years, they can be reactivated to serve the remainder of their two years.