For additional security and to optimize the performance of critical machines on your organization’s network, it is crucial to:.

Identify any program or services that you do not need.

Explanation:

As a network administrator, one of the preventive measures that could be adopted to complement your security system or architecture is to identify all the software applications or services that you do not need in an organization. This is because some of these programs might be a spyware, rootkit or compromised software which are used to gain unauthorized access to the network system. Also, you should identify the unused or unwanted programs or services in order to prevent redundancy and to optimize the performance of critical machines or processes in the organization's network.

Hence, for additional security and to optimize the performance of critical machines on your organization’s network, it is crucial to identify any programs or services that you don’t need.