katalepsy:
You are confusing static IP with dynamic IP. I use DHCP (dynamic) IP whenever possible which lets the router assign the IP address of the device. For those devices that I do not want the IP to change, like my Plex server for example, I tell the router to make the IP a permanent lease.
The only device in my home network with a fixed (static) IP address is the router itself.
Others here will swear by static IP addresses on everything. (Keeping track of all the IP addresses assigned is just not worth the effort.)
DHCP just simplifies things so much.