Mostly I wait for that squeaky wheel.
But...
I always make sure to monitor all interfaces for statistics. Configuring most ports as "Un-pluggable" so they don't alert but I still retain all statistics so that when the squeaky wheel shows up, we have the historical statistics to look back on.
I cant say how many times a company has wanted to swap out to 10GB to all users when they have never reached even close to 10GB aggregate across the trunk uplinks.
It used to be the same argument in the old days of folks wanting to go from 100Mbs to 1GB. It is really surprising to see how little the total aggregate is most of the time.
(Of course this changes a lot in the new landscape of things with so much multimedia going across the internet.)
On critical WAN ports I do keep an alert turned on for consistent throughput so I am alerted in that.
I also like to group high bandwidth interfaces and use a diagram to depict them with the atlas program in a specific custom view. For example I have the iSCSi storage interfaces in a single picture for our ESXi farms so we can easily verify bandwidth load is evenly distributed and we can see high spikes and such.
-What do you recommend Leon?
especially if someone has NTA, what additional reports or alerts would be most useful?