I was meaning to ask about this. I currently have a 2011 Mac Mini with a large internal SSD. I have defined several users. It is running macOS Sierra.
I will eventually have to move on, so I will have to use Mojave or Catalina. As mentioned in the article, installing a large internal drive (4TB or more) is expensive and, in my case, may not be feasible; I live in Chile, and Macs only come with standard drives. Thus, I have to consider external storage.
I understand that the internal drive must hold the OS and applications. How about user home directories? Can these be defined on the external drives? Alternatively, if home directories are defined in the internal drive, user files have to be stored and accessed externally.
I should mention that an important part of my work involves using virtual machines, which take a fair amount of space. What would be the recommended way to deal with this if I get a desktop Mac?