Each monitoring method answers a different question. Agents answer 'what is happening inside this host?' SNMP answers 'what is this network device reporting?' ICMP answers 'is it reachable, and how fast?' Syslog answers 'what did it say before it failed?'
Coverage without blind spots means matching method to asset class: agents on servers and endpoints where depth matters, SNMP on switches, storage and UPS systems, ICMP as the universal availability floor, and Syslog wherever the interesting events live in logs.
The guide includes a coverage matrix by asset class, threshold-setting guidance, and the noise-reduction patterns that keep the signal useful as coverage grows.