I went through the phase of having enough spare parts to keep all of my race bikes running until 3028AD, but have since learned that its just crap that clutters up your life. The difficulty I've had in selling some supposedly rare/valuable bits at half the accepted market value, shows that the "treasure hoarder" mentality is 95% bullshit - it might be rare, but its probably not worth going on with the "
my precious" routine that we're all (sometimes) guilty of.
I've lost count of the number of times people have knocked back decent offers for stuff I've wanted to buy from them, with the words "it's worth way more than that" - and six months later, its on Ebay for the fifteenth time, with a Buy It Now price that's below the offer I made...
Hmmm... that probably shows my current state of mind a little too clearly...
I guess what I'm trying to say is that it is very easy to be sucked into the hoarder mentality and/or convince yourself that all these piles of shit are going to make you rich one day. In reality, its probably just making your life harder and distracting you from the stuff that actually matters.
One thing that works really well, is when you've got mates with similar bikes and you have a shared parts pool - it nominally belongs to one of you, but it will be made available to anyone who actually needs it. That way you've got access to all of the bits you (might) need, without having to have too many piles of stuff hanging around just in case.