What happens if I open up a live .php file and just paste new working code and hit "Save"? What happens on the end user-side if I do that? Furthermore, I'm with DO and I don't think I've ever rebooted my virtual server.
Ah, I was unclear. When I said restart your web server, I didn't mean to reboot the machine. Just restart the web server process. Nginx or Apache or whichever you're using.