Update 12/2017: It will need an update/rewrite since Spring Boot 2.0 is coming.
Having metrics collected is vital for ...just anything, besides relationships maybe :) My favourite quote by Deming goes like this: "You can't manage what you can't measure". Without it either your experience, prediction and planning skills are so awesome that everything works as expected, or you're just deluding yourself. It's hard data that gives you feedback to confront your actions with reality. It's not only important on company-wide level, or in project management, processes, or when counting conversions in Google Analytics. There are metrics you can collect down on the application level, so can have insight on how it is performing, being used and that it works at all. A nice tool exists for Spring Boot apps to do that, and this is Spring Actuator I'm going to write about today.