So if you're going into one of the most physical branches of the services, like the Marines or Army, I'm sure that it'll help you immensely if you embody the physically adept soldier they want to put on display when it comes time for promotions.
https://www.thebalancecareers.com/marine-corps-enlisted-promotions-4052034
Marines use a "composite point" system. Promotion points within each MOS are determined with promotion points that are awarded for the following:
Rifle Marksmanship Score Determined based on the Marine's score on the rifle range. See conversion chart to convert rifle range scores to promotion points.
Physical Fitness Score Determined based on the Marine's latest physical fitness test. See conversion chart to convert Marine Corps PFT scores to Promotion Points.
Average Duty Performance Ratings A Marine's duty performance is rated periodically by his/her supervisors. The ratings used for promotion points are the average of all the duty performance ratings received since the last change in rank (promotion, demotion, etc). The average of duty proficiency marks are rounded off to the nearest 10th (4.44 would be 4.4; 4.45 would be 4.5).
Average Conduct Ratings Like duty performance ratings, a Marine's conduct is rated periodically by his/her superiors. The ratings used for promotion points are the average of all the conduct ratings received since the last change in rank (promotion, demotion, etc). The average of duty conduct marks are rounded off to the nearest 10th (4.44 would be 4.4; 4.45 would be 4.5).
Time-in-Service The number to be used is the total months in service (U.S. Armed Forces--active and Reserve) accrued in the military.
Time-in-Grade The computation of the total months in grade includes the number of months in the present grade on the current enlistment and the time-in-grade in the current or higher grade from a previous enlistment (USMC or USMCR [SMCR or IRR]), if the service was satisfactorily performed.
Drill Sergeant/Recruiter/Security Guard Bonus Points Commanders can add 100 bonus points for Marines who are performing duty as Drill Instructors, Recruiters, and Marine Corps Security Guards.
Self-Education E-3s and E-4s competing for promotion receive bonus points for military and civilian education. See conversion charts for points that can be awarded.
Command Recruiting Referrals E-3s and E-4s can refer individuals to recruiters. If those individuals then enlist in the Marine Corps, the E-3/E-4 will receive 20 bonus points for each individual referred (Note: Marine Corps Recruiters are not eligible for these referral points -- but they are eligible for the 100 point Recruiter Bonus, above).