Here's a tip to tame that tangle of wire that's sulking in your 'stash': Use Velcro Tape! And using white Velcro will allow you to mark the wire gauge on it.
Measure around the inside of a roll of wire. Cut a suitable length of the two-piece tape, so the toothed side of the tape overlaps the loop side, by about half an inch. This will allow the tape to 'fasten' on itself.
If the Velcro tape is too wide to fit inside the reel, it can easily be made narrower by cutting down its length. Remember that the loop portion goes in the reel first, with the tooth portion on top, and overlapping it a bit. As you use the wire, you can easily adjust the wrap to fit the remaining amount of wire.