Setting up baseline performance monitoring allows the administrator to understand the normal operating parameters of the web application. When a performance metric deviates from the baseline, it is an indicator that something is potentially wrong. Adding an alert for 95% CPU usage might be too late if the application starts slowing down at a lower threshold. Monitoring only during peak hours assumes knowledge of when peak hours occur and can miss performance issues arising at other times. Monitoring the number of concurrent users is useful but does not directly relate to the server's performance and response times.