I have about 5 or 6 whites right now! I go through them like water. You need a good sharpener, and a gentle touch. As soon as the blade starts to go, replace it. Those pencils are so soft and break so easily. Store them so they don't get tossed around. The more they are jostled, the more likely to break.

The sharpener I use is from Kohl-I-Nor, and is in a wooden "case" opposed to a metal or platic one. It gives nice sharp points. Sometimes a sharpener just won't give those pencils a point, no matter how hard you try. I got it at either AC Moores or Micheals.