The standard procedure for preventative maintenance is to regularly check for software updates as well as to look for physical damage to the device. Don't forget to clean the equipment properly as well.

For performing the preventive maintenance, before making any changes in live operation always do or perform a backup so that you will have a plan B when everything goes wrong. Always check the appliance physically for fan, or any obstruction in the cooling systems, and last always update to the latest patch for any security vulnerability.

Preventive maintenance checklists;
1) Workflow standardization and increased productivity.
2) Faster troubleshooting.
3) Better maintenance planning.
4) Licenses/Certifications expiration dates should be carefully maintain.
5) Network health checks and logging/reporting should be check time to time.

For performing preventative maintenance, always do or execute a backup before making any changes in live operation so that you'll have a plan B in case something goes wrong. Always physically inspect the appliance to look for a fan or any obstruction in the cooling systems, and always install the most recent patch to address any security flaws.

Obviously
1.Backup current device state including FW conf. & password*.txt
2.Do update itself.
3.Check if device works as expected.

Regularly checking for software updates and inspecting the equipment for physical damage are part of preventative maintenance best practices. Don't forget to adequately clean the equipment as well.

Preventative maintenance best practices include monitoring for software updates and assessing the equipment for physical damage on a regular basis. Don't forget to clean the equipment properly as well.

Regular, normal maintenance is referred to as preventive maintenance since it helps keep equipment operational and minimizes unscheduled downtime.
What about cleaning the appliance? It's always a good idea to backup your current running configuration to an external location while performing preventive maintenance. This is quite helpful since you can always restore the running backup configuration you stored if your appliance has any problems. Another option is to designate a spare port in your appliance as your spare management port so that, in the event that the default management port experiences a problem, you can manage your appliance directly using your spare management port.