The majority of the time, we have no idea what the IP addresses of our devices are. You don't need to know that your phone has an IP address of 192.168.1.12 on your local network in order to use it.

I often have to find the IP address of a machine I'm working on (or need to work on). Sometimes, I need to unblock an IP address of a machine on my network, so the machine can reach a network share ...