I can't tell you how many times I've bought a piece of audio gear with the full belief that it was a cornerstone piece that I'd keep forever. Hah, never happens. Technology changes, my musical needs change, this Nervosa kicks in, and, damn, time marches on.
I think the greatest value to me is my music collection and that has probably always been true - back when I had a big collection of reel-to-reel recordings, back when I focused on high-quality cassettes, back when I collected a lot of CDs (many from MoFi, XRCD, etc...), vinyl throughout (and still today), and now my rather large collection of FLAC albums with many hi-res 24 bit recordings that I listen to via Roon. I've probably had many of the same albums in all formats. So, the biggest VALUE to me (and likely the largest investment) is all the music I've collected, listened to, and discarded (tapes, cassettes and many CDs now) over the last 50+ years.
But that just might make me a dinosaur given the numerous hi-res streaming services now available. But hey, no regrets. I love the music, and I've totally enjoyed collecting, cataloging and listening to all of it.