You are looking for recommended thresholds and alarms on these objects. Unfortunately, there is no magic number that says what percentage utilization would be a good threshold to trigger an alarm. If a device has been running at 80% memory pool utilization for a while without a problem, there is no need to trigger alarms for the device. However, if a switch or router was using 10% of the memory pool in the past and the utilization suddenly shoots up to 70%, you will probably want to know about this.