It's been 25 years since I started using nmap and it's still one of the first things I install in a new OS.
To do what? Serious question
Why? It was cool when I was starting and wanted to feel like the supah hacka scanning ports with `-T INSANE`. Nowadays I just use it sporadically through nix-shell to identify unknown or suspicious IP in the network (which happens a lot since macvlan containers change MAC address all the time).
the use of nmap could get you expelled at my university 😆 I don't know if they ever enforced this rule.