I always maintained a large bin of colored pencils in my art room, and would purchase about a dozen sets of the cheapest pencils I could find each year to add to the supply as old ones were used up. I know there is a difference in pencil quality as to certain brands, but in the final analysis, the kids just like a large variety of colors, and I don't think the differences are so great they are worth worrying about. One thing all colored pencils have in common is that they float in a hollow wooden casing, and therefore are prone to breaking when dropped, which happpens all the time. Sharpening them becomes a challenge because any sharpener you use encounters the broken parts, which you can't see.
My solution to the problem was to not worry about it! I used an electric pencil sharpener for myself as well as hand sharpeners for the kids, mostly to prevent them being out of their seats all the time sharpening. I purchased inexpensive hand sharpeners, which I could,at the time, buy by the gross at Oriental Trading for really, really cheap. No worries about losing a few, and the quality was surprisingly decent. I found that the wall-mounted old fashioned sharpeners did not do well with kids, mostly because of the kids pressing down on the pencil at an angle that prevented the pencil from shapening the right way.