Seriously, don't toss that jump ring or scrap piece of wire you think you'll never use!
I learned long ago to save leftover wire, odd-size jump rings, and even components I made that didn't quite fit a project whether design-wise or aesthetically.
You never know when those pieces will come in handy.
If you don't already have one, get an organizer box with compartments. Fill it with jump rings, wire scraps, paddle and balled-end wires whatever you've got.
I have a box full of these odds and ends, and they've saved me more than once, like when I needed last-minute embellishments for a necklace.
Honestly, I keep just about everything (and yes, my workspace shows it). Sometimes I consider a clean-out, but then my {in}sanity kicks in and I wonder why I'd ever throw useful things away.
Even stones end up in those boxes because hey, you never know...