I try to keep a watchful eye on the 404s reported by nginx and the 500s generated by the rest of my stack. Gives you an idea of which exploits people are trying

I try to keep a watchful eye on the 404s reported by nginx and the 500s generated by the rest of my stack. Gives you an idea of which exploits people are trying to use against you. And how frequent or big of a target you are to them.