This is what I do.
If there is a point in the game where it could, possibly, in some way, become useful again, then I will keep ahold of it. I would rather drag some stupid piece of armor around and NOT need it, then realize 'oh snap, there's a boss fight right in front of me that it would be REALLY nice to use it on, but I need to buy it...again.'
There was honestly no game that this was more relevant in than the first .hack series. Lugging around six different blades at all times...yuck.