Bottom line
You have to stay medically ready, and a lot of that is on you. Get your Preventive Health Assessment (PHA) and physical done on the schedule for your age and status, report any injury or illness fast, and keep your records current. If you get hurt or sick, your medical status changes (TNPQ, NPQ, or Line of Duty), and each status has its own rules, timelines, and paperwork. This section also covers HIV testing and policy, DNA sampling, deployment health screening, where your medical records go when you leave, and the rule that you cannot draw both VA disability pay and military pay for the same day.
What it means for you
Three things drive everything here. First, exams: under 50 you need a completed medical exam within the last five years, 50 and over every two years, 60 and over every year, plus your annual PHA. Miss a required physical with no remaining service obligation and you can be moved to the Standby Reserve involuntarily. Second, getting hurt: if you are injured or sick off duty, you have five days to notify your command, and your documentation must reach the unit by the next drill. Money and medical care depend on the status you land in, so do the paperwork. Third, leaving: when you separate, transfer, or apply for VA benefits, your records have to ship on time so the VA can act on your benefits.