I started collecting vintage computer stuff fairly recently, about 6 months ago, after watching Triumph of the Nerds which is a rather long movie summarizing the start of the modern computer revolution (pretty interesting and worth the time to watch for those who haven't seen it yet).
This led me to wanting an ALTAIR 8800 so naturally I looked on eBay but none were for sale. So I waited and waited, and then gave up. Someone suggested I forget about it and instead get the earliest 6502, 4004, 4040, 8008, 8080, and Z80 which I did, but doing so costing me a fortune.
Then by pure chance as I was getting ready to go to bed one evening a pristine ALTAIR showed up on eBay for a reasonable price, so I picked it up. Turns out the seller also had some other vintage gear so picked that up as well. Then met another individual who was clearing out an estate and had tons of neat documentation and ALTAIR BASIC on paper punch tape, so I picked that up as well.
And very recently, also by pure luck an even earlier ALTAIR popped up on eBay for an extremely low price, so how could I resist? Bought that one as well. Now I have 2 ALTAIRs and some other very interesting vintage items.
Anyways, long story short, I spent way too much money over the past few months and am limiting myself to documentation from now on. Don't intend to sell any of my stuff ever and have just enough space for the collection that I have as it is right now, thankfully.
My personal opinion is that if you are in possession of IMPORTANT and HISTORICALLY SIGNIFICANT vintage computing gear, you must understand that you have a responsibility to care for it. If you are unable to do that, or don't have the space for it, you should sell it or give it away to someone who does. The worst thing is to throw it out. Can you imagine someone throwing out an Apple I or early Apple II?
Also many people consider IBM clones or ALTAIR-like computers to be collectable items. I disagree. Those computers were made to profit off the success of the initial computer that came out first, and they hold little to no historical value. They didn't usher in anything revolutionary.
I still debate the historical significance of the IMSAI for instance. It was a better overall machine than the ALTAIR but did it really introduce anything revolutionary or significant? Not really. Any many computers that followed the IMSAI are even less important so why collect them? Those you can give away to kids or anyone who wants to tinker and play around with it. If they short circuit something inside then it's no big deal. But short circuiting an ALTAIR? What a terrible thing to happen.