I really believe only two levels are necessary most of the time: error, and info. Error is for anything that a dev should be notified about (AKA if you send an

I really believe only two levels are necessary most of the time: error, and info. Error is for anything that a dev should be notified about (AKA if you send an error log message, assume someone will be notified about it immediately), and info is for any other useful debugging information, like "we got a request for /foo/bar at 10 pm". I also think structured logging is absolutely essential. Log levels are really just a way to get some of the benefits of structured logging.