What do you do with all the leftover components from a server purchase?

Solution 1:

Put them in a box in the back of some storage area. Only when the server is replaced should these bits and pieces be disposed of. Things change and you can never be totally certain of what you may or may not require in the future. Some of that stuff you describe can be used to maintain other machines, even if only temporarily.

Solution 2:

If you buy enough kit from HP they'll give you built-to-order kit at set-config prices so I tend not to be left with spares. What I do have ends up collecting dust in storerooms then being thrown out years later :)

Great question btw.