Which best practice is important for securing ArcGIS Services?

Applying least privilege access controls is crucial for securing ArcGIS Services because it limits the access and permissions granted to users and processes to only what is necessary for them to perform their specific functions. This minimizes the potential attack surface and reduces the risk of unauthorized access to sensitive data and services. By ensuring that users have only the permissions they need, organizations can protect their data from accidental or malicious actions that could compromise security.

In a secure environment, it's essential to regularly review and fine-tune these access controls based on changing roles and requirements, thereby adhering to the principle of least privilege. This practice not only safeguards the organization's resources but also enhances overall system integrity and security.