Hoarding is a real deal, and its root causes are complex — tied in things like PTSD, grief, etc., long preceding the starting of that hoarding (I’ve had both friends and family of friends who’ve struggled with hoarding, and it was hard to bring up with them, if it was at all even possible).
On a more pragmatic level, it really comes down to whether what one has is going to be used actively in the near future or not. If not, then it’s time to let it go. This goes for computers, appliances, paperwork, whatever (and where the last two intersect: the paper shredder, which in this house gets plenty of use).
For Macs, as that’s the ever-present topic here, every Mac in my signature, minus one (for, well, at least another week or two) is in active, daily use, has set use-cases for my needs, and each has a comfortable home on a desk (of which I have three in my home, each serving as a different work area for different purposes: day job work desk, film scanning and audio engineering desk, and DJing and keyboard practice desk). One iPod nano from my signature line lives on a 30-pin mount equipped on my bedside alarm clock, while the other goes with me wherever I do (and also comes along as emergency fallback at DJing gigs should there ever be technical failure preventing gear from getting the live show out on time).
That said, as a reader, scholar, writer, music archivist, DJ, and photographer, I do cop to hoarding data, but we’re at a point now, really, in which data can be managed and tucked away sufficiently inside a compact NAS or a server.