I have always been taught that the quality of your craft work is invariably limited by the quality of your tools. The most important part of any tool its cutting edge. In miniatures we are constantly cutting paper and foamcore. It is essential that the knife blade (usually of an xacto knife, less often, of a utility knife) be very sharp at all times. Sharp blades are actually safer than dull ones, as they are less inclined to slip.  And, of course, to make a clean cut, a sharp blade is essential.

One can always purchase a packet of blades for your particular knife, but, using a blade dulls it rather quickly, so, doing a large project can become quite costly. The one time purchase of a fine sharpening stone can alleviate the necessity for purchasing innumerable blades. Such stones can easily be found in the tool department of a hardware store, large home building centers like Home Depot, and at various online websites. You want to acquire a very smooth stone - not a rough one - as the stones do come in various grades. The process of sharpening is really quite simple.