In every book on colored pencil art the author tells you to buy a good electric pencil sharpener that sharpens to a fine point. I love using an electric pencil sharpener, but my experience is that we have a tendency to over sharpen, and it eats pencils up quickly. I suggest that you purchase a small hand held sharpener like you kept with your school supplies as a kid. Buy it at an art store, because it will have a better blade in it. You will need to replace the sharpener as the blade becomes dull, but they are cheap to replace. The blade on an electric sharpener also becomes dull, and replacement is much costlier. If you want an electric sharpener X-ACTO and Boston are good brands and can be found at Staples, Office Max, Amazon and fine art stores. You'll get the best price on Amazon. If you plan to take work to the coffee shop, bookstore, or library, buy a battery operated pencil sharpener.
I had to throw my last Boston electric sharpener in the trash after a lead broke off in it. Believe me, I tried and tried to get that broken lead out, but it wouldn't budge. If this happens to you, and it will, take a number two pencil and sharpen it. The harder lead of the number two will break up the soft, colored-pencil lead and your sharpener will work again. This works 99.999% of the time. I'll still buy Boston electric. I don't blame the brand for this mishap. It was just one of those quirky things that happened.
As an after thought, I read several reviews on Amazon about pencil sharpeners. Over and over customers said things such as this: "I purchased my pencil sharpener two years ago. It worked great at first, but now it doesn't sharpen very well." "My battery operated pencil sharpener worked fine at first, but now it has slowed down and the pencil isn't very sharp" These statements were all accompanied with low ratings.
I reiterate: You must periodically replace your pencil sharpener, and change the batteries on the battery operated sharpeners.
This goes for all three styles. The electric sharpener will last the longest, and the battery operated sharpener lasts longer than the manual sharpener.