It's not just a waste of disk space. It can speed up your system.

The main thing I am unsure about is the RAID1 thing. Is this a good idea? How do I set it up? I imagine it won't be quite as easy as telling him to use some space on sda to mirror the stuff that ...

Void Linux is a unique and highly customizable Linux distribution that stands out due to its independence from other distributions and its use of the runit init system instead of systemd. This guide ...