I use mechanical pencils with 2-mm leads for drawing as much as I can and I prefer them for several reasons. Over the years, I've collected several different types and colors and have consistently kept the same hardness of lead in each one. This creates a color coded system that allows me to find the hardness of lead I need with a quick glance. Leads in a holder are quicker to sharpen than wooden pencils and the leads are less likely to break, too. Just a few rotations around the sharpener creates a long sharp point.

Mechanicals are more economical and ecological than wooden pencils, also. While you could buy several wooden pencils for the initial cost of a lead holder and sharpener, the less expensive replacement leads save you money in the long run. And, of course, using mechanical pencils saves trees.

I still keep a few wooden pencils around, though. Sometimes it's hard to find replacement leads at the extreme ends of the hardness scale, so I keep a few 9B and 9H woodens around for back-ups. Sometimes I prefer to do quick sketching with a wooden pencil, too, because you can lay them down on their side and use the full length of the lead. It's hard to do that with a lead holder because they don't taper back from the lead as elegantly as wooden pencils do.

You probably started out with a set of wooden pencils as most people do, and when it's time to replenish your supply I suggest that you buy a lead holder, sharpener, and a few leads to see how you like them. The holder and sharpener will last for years and you'll save money and trees, too.

Read more about pencil types here.