No network can be declared permanently secure. A more useful question is whether you have appropriate controls, useful visibility and the ability to respond when something changes.
Can you identify every connected device?
Unknown or unmanaged devices create blind spots. Maintain a current inventory and define which types of equipment may connect.
Is access appropriately separated?
Guest devices, staff computers, administrative systems and critical servers should not automatically share the same level of access. Segmentation can reduce the impact of compromise.
Are important events visible?
Logs and alerts should help you recognize repeated login failures, unexpected administrative activity, unusual data movement and security-control failures.
Can you restore operations?
Backups must be protected, monitored and tested. Recovery planning should identify essential systems, responsible people and acceptable downtime.
When was the environment last reviewed?
Networks change as employees, software, devices and suppliers change. Regular assessment helps ensure that documentation and controls still match reality.