Udev rules will work but I always forget such customizations if moving OSes or replacing hardware.
Certain OSes will make symbolic links to the serial devices in certain places that are persistent no matter what USB port is used. In other words, you can reference the usb device through a link instead of explicitly defining the device.
For example, my aeon zwave stick has a device id of 0658:0200. This was determined by running lsusb and seeing this:
Bus 001 Device 004: ID 0658:0200 Sigma Designs, Inc.
Knowing that home-assistant references the serial tty device, you can start looking under folders in the /dev/ folder (in my os, I see this)
ls -l /dev/serial/by-id/ total 0 lrwxrwxrwx 1 root root 13 Jun 10 08:52 usb-0658_0200-if00 -> ../../ttyACM0
In the configuration yaml, I set the path to the link…
zwave: usb_path: /dev/serial/by-id/usb-0658_0200-if00