I strongly identify with this. Although sometimes I think it's justified - no use using a great name on a throwaway 'extra' in a scene when it might be a great primary character in a later work. Names have to be right for me which often stymies me (and makes fanfic easier to work with! I might hate the names but they're there, and that's all there is to it) so if I do love one, I might hold it 'in reserve'.

But sometimes, yes, I hoard things, worried that I'll only get to use them once, and that might be the wrong decision. Thanks for a thought provoking read :D