Depends on the distro, but it's trivial in ubuntu-based and no harder than the rest of basic setup in arch (the only two I have recent experiece with). I'd argue that any distro where it isn't easy is a good reason to start looking elsewhere, absent any specific conflicting requirements.

Not sure it matters if it's full-disk vs just home directory, but full disk is easier to reason about and I don't recall an OS that can do homedir easily but not full-disk (there very well could be one, just none come to mind).