I've built up a few vintage bikes over the past couple of years, and there are plenty of parts to be had on
eBay. The problem is it's hard to know what combination of components will work best, but as there's so much going cheap I just bought a load of stuff with the intention of choosing what works best and reselling the rest - chainsets, derailleurs, stems, handlebars, brakes...
The trouble is, I didn't really get round to the second part of the plan - the reselling bit. I have sold things I genuinely don't like and will never use (like a Biopace 52/42, which is no good for my old legs these days) and I've given away a few bits where there's clearly a better home for them than mine.
But with the parts I have left, I can't help thinking I should keep them on the off chance I might build another vintage bike or two next year
And it brings me to another thought I've often had... Looking at the silly low prices that good old bikes (with good old components) go for on eBay, I'm convinced there's profit to be made by buying and stripping them and selling the components. But I just can't bring myself to what I see as an act of destruction.