Other than the following items, what else do you monitor or watch out for on your routers/switchs?
- Interface status (up/down)
- Interface errors/discards
- Interface utilization
- CPU utilization
- Hardware status (fan, PSU, etc)
- Config changes
Should you monitor memory usage? This would seem odd since you'd need a good understanding of memory allocation in IOS.
Some other things I had in mind (though I'm not sure if you can monitor them):
- HSRP active router (where applicable)
- Default route (in cases of default route being received from BGP neighbor)
- BGP preferred path