I died (boo) and came back to life (hurrah!). I was pooped and had 12 (of 480) energy, so decided to use up the dregs of my energy by repairing my Fancy Pick. I found that it would repair it one "block" and then stop, without taking away any energy. I repeated this several times and it never took any energy, but the condition of the pick kept improving. I didn't try to repair it to 100% because that felt a bit like cheating.