Operations monitoring is the baseline for troubleshooting. Only if you are watching the essential layers and nodes in the network can you hope to effectively identify the cause of problems when they arise. It is one thing to address connectivity and protocol issues, but without a firm grasp of what should be connected and how the protocols should operate, the network is visible only when it is malfunctioning.
Imagine driving a car without a fuel gauge, a low oil indicator, or even a speedometer. It's possible you might drive around until the car stopped and then, first, try putting gas in it to see if it will start again. But if the engine had seized because there is no oil, you would be wasting your time. Even if the car runs, without a speedometer, you might wonder why the police keep stopping you and giving you tickets.
That's what it's like to have a network without adequate operation and monitoring tools.
One of the most valuable troubleshooting tools you have is the ability to say, “Show me a good one.” When someone complains that things are wrong, it's important to know what's right. Unless you have set up ways to monitor and operate your network in good times, you'll be hard-pressed to zoom right to the trouble area in bad times.
Some people may imagine that their network is too small to expend resources on keeping elaborate event tracking ...