Funny you mention it but me and the wife were talking about this today - because she thinnks I really need to hold onto things as long as I have space.
I go through a phase every few years or so where I decide to "downsize" the collection, and more than half the time there's a bunch of stuff I miss and then end up spending more $$ getting back afterwards. This has happened several times.
Regrets?...I have a lot, I've been doing this hobby that's been a good exercise for my IT pro life for 20 years now....
- I really regret selling my Compaq Deskpro 386, it was one of the early 16MHz models from 1986 and an AWESOME machine, and I had the matching amber mono monitor for it to boot (running in EGA no less).
- I also regret the XT I sold at the same time, it was destroyed by USPS in shipping and I had to refund the buyer all his money
- Sometimes I do wish I had the IBM PS/2 Model 30 286 back too, the fire damaged one.. another cool setup I sold off to only have "one" of each generation at most - had the 8514 CRT, and first gen PS/2 mouse, and Model "M"
- I do regret letting go of the IBM ThinkPad 755CD I had but it was so worn out and beat up it looked like it was about to crumble to pieces any moment before I parted it out, I used that as my main laptop from 2005-2008.
- A lot of the old 486's I had because I had some cool ones, and I LOVE 486 era hardware the best.
Some stuff I might be able to get back, like the original mother board from Creeping Net 1 (Zeos 386/486 upgradable systems main board), and I think my AT&T Safari 3151 might be living in my childhood closet as well. When I moved out of my childhood home in 2005 I left a few things there. Not sure if I'll ever get them back or not though. The AT&T was dead when I left it up there but I migth be able to fix it with my current skillset.
I was discussing moving possibly to using just NEC Versas for the 486 and Pentium hardware as they all can share the same docking station - thusly saving space. Then keeping the GEM 286 for the XT and AT era stuff and adding a Tandy 3-voice card to it. But my wife is partial to the little Mac SE, likes the Tandy for it's "80's ness"....wife says "I know computers are one of your biggest things so don't rush into it (this time), because you'll just end up replacing the things you miss or want back. As long as you have space for it, I say keep it."....sometimes having an S.O. can really help.....also, might be able to go more "tech tree" this year at xmas (we did a technology theme to our x-mas tree last year and it looked cool as heck).