If you’re running a production application, you need metrics. There are some great paid products out there that allow you to gain visibility into how your application is performing. You can save a few bucks by using Prometheus with Grafana and hosting them yourself.
Junior developers are often ignored when inviting engineers to review code, due to a perceived lack of extensive knowledge or expertise. But involving such a fresh pair of eyes, however junior, can greatly benefit you, your team and your code.