If it's there, mount it
I've been trying to sort out my build environment; I've been using a USB disk (as in spinning), mounting it by hand as the home directory of a separate development account. Wouldn't it be better, I thought, to mount the disk when it's there and ignore it otherwise. Guess what? You can, /etc/fstab now looks like:
UUID=a7ad21a6-6458-4d33-bc80-c87e189ca798 /home/david ext4 nofail,auto,errors=remount-ro 0 1
Note: you could use the disk name, but using the UID is more portable.