If you use wooden pencils you need a sharpener you can carry. Something that doesn't take up much space, but does a good job. There are some great choices out there, but my favorite is the KUM Masterpiece.
If you're serious about pencils you'll want something better than a .50¢ sharpener. Thankfully none of the portables are very expensive.
You can go with a small brass sharpener like the one by Dux pictured above. It will give you a short point and it takes up very little room in your pencil roll or bag. Dux makes great sharpeners worth having. Here's another example.
The Palomino Blackwing Long Point sharpener (also pictured above) is definitely an upgrade in terms of the point it puts on your pencil. It's a two-step sharpener like the Masterpiece, which I will explain below. This is a good option, but if you're going in the long point direction you're better off jumping to the KUM Masterpiece.
The KUM Masterpiece is a German made two-step sharpener that leaves the longest and sharpest point possible by a small sharpener. It's only $15.00, but it's not available through Amazon yet. So you'll have to go through something like pencils.com to get it.
A two step sharpener, like the Masterpiece, works by using two different sharpening blades to get the super fine point. The blades are numbered 1 and 2. The first blade (1) removes the wood from the end of the pencil without touching the lead. This allows for a long point. You twist the pencil until it stops shaving the wood as the exposed lead eventually presses up against the blue plastic end.
The second blade (2) is designed to sharpen the exposed lead. Turn the pencil, applying light pressure, until the lead is sharp. If you begin to shave wood you've gone too far.
The KUM Masterpiece is an amazing sharpener. It may sound silly to hear someone say that about such a small thing, but if you compare it to others it really stands out. This sharpener is smaller than the Palomino, and comes with a plastic case and a pouch. I use neither, but it's all very nice.
"Why would someone want a long and sharp point on a pencil?" "Won't the lead just break when I try to write?" I've been asked these questions by a few people. First, a long point is helpful when sketching and shading as there is more exposed lead to use. If you draw in your journal like I do this is helpful. And while a long point may break easier, it encourages a gentle touch which is best for writing anyway. Of course, a sharp point makes for cleaner writing. Some pencil leads will break easier than others. It depends on the hardness of the lead (this is determined by ratio of graphite to clay). Softer leads will break more easily that harder leads. I typically use a B or a 2B and I don't have any problems.
If you're getting into all this pencil stuff, I'd encourage you to get the KUM Masterpiece. But ultimately, just get something you like that works well.