Corporals need the opportunity to be corporals before they become sergeants.
Starting in January, corporals won't be able to pick up sergeant until they've been in the Marine Corps for four years. That's twice as long as the current requirement.
And sergeants won't make staff noncommissioned officer status until they've served at least five years -- a year longer than currently required. Sergeants will also need 36 months time-in-grade before they can make staff sergeant. That's up nine months from the 27 required now.
Black told Marines that about a third of new sergeants are leaving the service within a year of picking up rank.
"Quite frankly, we can't afford to lose about 30% of our sergeants every single year," he said. "... We need sergeants on flight lines, we need sergeants in squads, we need sergeants doing what they're supposed to do, and we need corporals to ... master their responsibilities to reach the next higher paygrade."
Starting in July, new staff sergeants will also owe the Marine Corps at least two years of service once they pin on their new rank.
"Marines who are selected to the rank of staff sergeant must have at least 24 months of obligated service remaining on contract beginning on the date of their promotion," states Marine administrative message 612/19, which announced the changes.
The service already requires gunnery sergeants to serve at least three more years after pinning on that rank, Black told the Marines in Yuma, Arizona, where he discussed the policies last week.
"What's the benefit of that?" asked Black, who previously served as the top enlisted leader of Manpower and Reserve Affairs. "If about 30% of people who get selected to staff sergeant ... and don't stay at least 24 more, that speeds up promotion from sergeant to staff sergeant, that speeds up promotion from corporal to sergeant. You start to lose experience along the way."
That's because the Marine Corps promotes to fill vacancies, said Yvonne Carlock, a Manpower and Reserve Affairs spokeswoman. A lot of corporals were picking up sergeant before they hit the end of their first four-year enlistment, only to leave the service at that point, she said.
To fill those voids, the Marine Corps would again tap into the corporal ranks to promote more Marines to sergeant, and the same pattern was repeated.
"The reason we're doing this," Carlock added, "is to reduce the churn."
The move hasn't been popular with everyone. One Reserve Marine career planner told Stars and Stripes "nobody is going to want to wait four years to pick up sergeant." And a corporal told the outlet if the changes leave fewer Marines making sergeant, that could mean "less structure in the ranks."
Marine officials say the opposite will be true -- that the moves will keep more newly promoted noncommissioned officers and staff NCOs from immediately leaving the ranks.
Along with the new promotion rules for sergeants and staff sergeants, the Marine Corps is introducing new initiatives to help retain enlisted leathernecks. Carlock said the moves are meant to improve processes.
Marines who demonstrate "high levels of proficiency and talent must be given the most efficient means by which to request and be approved for reenlistment and subsequently be provided opportunities to excel in critical leadership roles," the administrative message states.
A select number of Marines will be allowed to submit their reenlistment packages a year ahead of schedule. The move could also leave them eligible to receive reenlistment bonuses and other initiatives that apply to Marines choosing to stay on another term in that fiscal year.
"Under current policy, [a Marine] with an end of current contract (ECC) of April 2022 is considered an FY22 cohort Marine and is currently required to wait until July 2021 to submit for reenlistment," the administrative message states. "Under Early Reenlistment Authority, this Marine, if a computed Tier 1 Marine with no jeopardy on current contract, will be allowed to reenlist as early as July 2020 during the FY21 Enlisted Retention Campaign."
General officers will also be given the authority to approve some Marines' reenlistments without sending requests to Headquarters Marine Corps.
"[Major Subordinate Command-level] General Officers will be allocated a specified number of reenlistments for approval based on the percentage of the eligible cohort assigned to their command," the message states.