Final answer:
Reentry control packages are updated at a command as per operational security policies, which can vary by entity. The specifics of these policies are often classified and regularly reviewed to ensure safety and integrity.
Step-by-step explanation:
The frequency at which reentry control packages are kept and updated at a command can vary depending on the specific protocols and requirements of that military or government entity. Normally, such procedures are informed by operational security policies and the need for ensuring up-to-date information for personnel who may require reentry to a secure area after deployment or travel. The specifics of these policies are typically classified or require a certain level of clearance to access, and as such, they are not publicly shared details. In most cases, however, it is standard procedure for commands to regularly review and update all security measures, including reentry control packages, to maintain the integrity and safety of the command.