Not a functional advice (my old laptops still all serve the same function), but: I'm using Apple since 2014 and realised I've gathered quite stack of old Macs

Not a functional advice (my old laptops still all serve the same function), but: I'm using Apple since 2014 and realised I've gathered quite stack of old Macs (one Macbook Air, one MBP and one iMac). I've installed Linux in all of them for the heck of it and its quite a welcome break for macOS. I try use the old Macbook Air only as a thin client (tiling window manager and most TUI applications for IRC, email, coding, remote admin, etc).