Log messages also have to be defined first. I find it much harder to guess what log messages I will need in the future compared to what metrics. Metrics are e

Log messages also have to be defined first. I find it much harder to guess what log messages I will need in the future compared to what metrics. Metrics are easy: for any resource, service, component, and queue (explicit or implicit), you want to know cumulative arrivals, departures, timeouts, errors. That takes you most of the way there for most things. You can add counters for significant events too, but they tend to be automatically included by the above. (Basically departures from the component that trigger the event.)